CRYSTALLfSER HOLDING DEVICE Technical Field
The present invention refers to a crystalliser holding device, specifically a device suited to housing a crystalliser used in plants for the production of steet billets, blooms and slabs, suited to being fastened in an oscillating table. State of the Art
The state of the art includes numerous crystalliser holding devices, also known as cartridges, described in different patent documents.
Of these documents, patent GB2156252 deschbes a continuous casting device comprising a crystalliser inserted inside a crystalliser holding cooling device. This device in turn compnses an upper chamber for the distribution of the pressurised cooling fluid inside a space, or gap, between a crystalliser guiding wall and the crystalliser itself, and a lower cooling fluid return chamber. There are provided relative ducts for the entry of the fluid into the upper chamber and for the exit of the fluid from the lower chamber.
A first disadvantage of this casting device is that of providing an introduction of the pressurised fluid into the aforesaid gap, which inevitably entails a deformation of the crystalliser walis under hydraulic thrust.
A further disadvantage is represented by the fact that in the upper distribution chamber the pressuhsed cooling fluid generates a force that acts also on the upper closing flange, that therefore must be made with a great thicl^ness in order to prevent the deformation thereof under the considerable hydraulic thrust and, furthermore, must be fastened with a considerable number of screws to the support structure.
Furthermore, such a device makes the operation of replacing the crystalliser inconvenient in the case, for example, that the format of the product to be cast has to be changed.
A second example of known crystalliser holding device is that one described in the document US5715888. In this case, the crystalliser provides a longitudinal cooling gap, fed with a cooling fluid by a feeding chamber that is an integral part of the block containing the crystalliser and elements thereof are held together by mechanical fixing means. Such block is entirely extractable from the mobile structure of the oscillating table.

Disadvantageously, this configuration of the cooling fluid feeding circuit is also such as to deform the crystaliiser walls and to exert a significant hydraulic thrust on the upper closing flange that must therefore be fastened to the support structure with a high number of screws, which complicates both achievement of the crystaliiser holding device and the crystaliiser changing ope rations,-and entails high production costs.
The need is therefore felt to make an Innovativ-e crystaliiser that makes it possible to overcome the abovementioned drawbacks. Summary of the invention
The primary purpose of the present invention is to achieve a crystaliiser holding device or cartridge, containing a crystaliiser for steel billets, blooms and slabs production plants, that has a high constructive simplicity, a significantly reduced overall weight and that reduces substantially to zero the need fov maintenance. A second purpose is-that of achieving a crystaliiser holding device provided with a complete cooling system that, in addition to efficaciously guaranteeing the transfer toward the exterior of the heat of the liquid steel introduced into the crystaliiser, i.e. the so-called primary cooling, also provides-a separate circuit for the cooling of the continuous ingot exiting the crystaliiser and of the ro!lers-at the foot. A further purpose of the crystaliiser holding device of the invention is, lastly, that of making easy and rapid the replacement of"the crystaliiser in the oscillating table inside which it is housed.
The present invention, therefore, aims to overcome the drawbacks described above by achieving a crystaliiser holding device for casting steel products such as billets, blooms and slabs that, according to claim 1, comprises:
- a tubular crystaliiser defining a longitudinal casting direction provided with a plurality of longitudinal channels in its thickness for the passage of a first cooling fluid,
- a substantially ring-shaped casing an-anged at a first end of said tubular crystaliiser comprising a first chamber for feeding the first cooling fluid into said plurality of channels,
characterised by the fact that said crystaliiser holding device provides at least one first duct for the re-ascent of the first cooling fluid, said first duct communicating with a second chamber for recycling the first fluid provided in said casing.

The crystalliser housed in the-cartridge of the invention, which can be straight or curved, is provided with a plurality of longitudinal cooling holes or channels made in its thickness, which permits minor deformation of the walls thereof following the pressure of the cooling fluid that flows inside said holes, and therefore a greater overall stiffness and an efficient heat exchange between steel and cooling fluid, the holes or channels being very dose to the inner wall of the crystaliiser. Therefore, with respect to the solutions of the known art, the cooling fluid pressure advantageously does not negatively influence the geometry of the crystalliser and furthermore does not generate undesired forces on the upper fixing flange. The crystalliser holding device of the invention also makes it possible to obtain the following advantages:
- a low overall weight, thanks to its innovative constructive conformation, and therefore low/ inertia, not necessitating high actuation forces of the entire mobile structure of the oscillating table and allowing the use of small dimension table oscillation controls;
- the possibility of an extremely rapid crystalliser replacement, when necessary due to wear or format changes, thanks to the hydraulic'brackets clamping system placed at the summit of the table.
Auvantageously, the feeding manifold of said fluid, being part of the crystaliiser
holding "device, is fixed to the table by means of said hydraulic brackets: the
presence of fixing screws and bolts is therefore reduced to a minimum, if not
eliminated, and the replacement time is reduced to a minimum.
A further advantage is represented by the fact that the crystalliser holding device,
object of the present invention, allows housing in an oscillating table with a
particular configuration of the guiding elements thereof, for example pairs of
elastic bars having a round or flattened shape, that permit oscillation exclusively in
the casting direction and exclude ar\y ro!i movements around axes perpendicular
to the casting axis.
The dependent claims describe preferred embodiments of the invention.
Brief description of the figures
Further characteristics and advantages of the invention will be further evident in
view of the detailed description of a preferred, though not exclusive, embodiment
of a crystaliiser holding device, such as illustrated by way of non limiting example,

with the aid of the appended drawings wherein:
Fig. 1 represents a vertical section of a first oscillating table comprising a
crystalliser holding device according to the invention;
Fig. 1a represents a vertical section of a second oscillating table comprising a
variant of the crystalliser holding deviceaeeording to the invention;
Fig. 2 represents a section along the A-A"plane of the plane view-of the oscillating
table of Fig. 1;
Fig. 3 represents a vertical section of a first embodiment of the crystalSiser holding
device according to the invention;
Fig. 4a represents a vertical section of a second embodiment of the crystalliser
holding device according to the invention;
Fig. 4b represents a variant of a part of said second embodiment of the crystalliser
holding device.
Detailed description of prefen'ed embodiments of the invention
With reference to Fig. 3, a-fiTst:embodiment of the crystalliser holding device or
cartridge of the invention is represented. Such crystalliser holding device 34
houses a tubular crystalliser 30 and is provided with a manifold 7for feeding and
distributing at least one crystalliser cooling fluid.
Crystalliser 30 and-manifold 7 are solidariiy joined by an upper closing flange 38.
The crystaiiiser holding device 34 is-inserted into an oscillating table support
structure 20, suited to being oscillated by an oscillation control comprising for
example a pair of hydraulic or mechanical actuation means 3, such as cylinders,
provided on an externa! support structure 10 fixed to the ground.
The crystalliser holding device 34 comprises a ring-shaped manifold 7 for feeding
cooling fluids, obtained by melting or by means of an electrowelded structure,
which surrounds the head of the tubular crystalliser 30.
Advantageously the crystalliser holding device 34 is fixed to the oscillating table
thanks to the surface 60, which acts as a rest to the support structure 20, and by
means of hydraulic braci^ets 15, thus completely eliminating the presence of fixing
screws and bolts.
The crystalliser 30, which is preferably monolithic, is provided with longitudinal
cooling holes 5 made in the thickness thereof: this gives it greater stiffness and
makes it possible to avoid walls deformation following the pressure of the cooling

fluid.
The longitudinal holes 5 of the so-called primary cooling, being close to the inner wails 6 of the crystalliser, permit an excellent heat exchange and, therefore, the transfer of the liquid metai heat, inside the crystalliser, towards the outside, thus advantageously obtaining a lower rhomboidity of the cast product and a better external superficial quality thereof; furthermore, this type of crystalliser construction is able to maintain the design taper thereof over time. The primary cooling fluid, generally water, is introduced into the holes 5 from the top towards the bottom through a first feeding chamber 31 of the ring-shaped manifold 7, fed by hoses not shown. The feeding from the top towards the bottom allows a better heat exchange in the top part of the crystalliser. The inner wall of the crystalliser holding device 34 and the external one of the crystaliiser 30 advantageously define a duct 5' for the re-ascent of the primary cooling fluid. The longitudinal holes or channels 5 are in fact communicating with the duct 5' in correspondence with the foot of the crystaliiser 30, Advantageously, the ring-shaped manifold 7 also compnses the return circuit chamber 32 of the primary cooling fluid and a second feeding chamber 33 of the secondary cooiing fluid, preferably untreated water, that goes to feed the sprays tu, afianyeu in oorresponucncc WILII LMC luueit^ DU at ine I UUL uf LMO Oiysi.aiiiit:i ou, crossing a further duct or several ducts 5", made in the thickness of the crystaliiser holding device 34.
By means of the sprays 40 the continuous ingot is cooled directly upon exiting the crystalliser and, furthermore, the same rollers 50 at the foot are cooled externally. Advantageously, the presence of the three-chambered manifold 7 and the relative holes or channels or ducts 5, 5', 5", made in the thickness of the crystalliser walls and of the crystalliser holding device, allow a greater compactness of the entire ingot mould and a reduction in weight of the support structure 20, and therefore a lower inertia of the mobile part of the table that must be oscillated by the table. Preferably the longitudinal holes 5 are arranged in a parallel way with respect to one another and to the casting direction or axis X; and the chambers 31, 32, 33 are arranged inside the ring-shaped manifold 7 in a concentric way with respect to said casting direction. On a plane perpendicular to casting direction X, the crystalliser 30 may have, for

example, a circular or square or rectangular section or other form. A second advantageous embodiment of the crystalliser holding device of the invention is shown in Fig. 4a. In this case, the cooling i^uid feeding manifold 7, preferably but not necessarily ring-shaped, comprises only the primary cooling fluid feeding chamber 31 and the return circuit chamber 32 of said fluid. In addition to the longitudinal holes or channels 5 made in the thickness of the " crystalliser 30, only one or more ducts 5--are provided in the cartridge 34 for the re-ascent of the primary cooling fluid. Also in this case, in fact, the longitudinal holes 5 are communicating with the duct 5' in correspondence with the foot of the crystalliser 30.
Advantageously the secondary cooling, i.e. the cooling, with untreated water, of the continuous ingot upon exiting the crystalliser and of the rollers 50 at the foot, is made by means of one or more external water feeding manifolds, arranged in correspondence with the iowerend of the crystalliser.
A first variant of this second embodiment, illustrated in Fig. 4a, provides an external manifold 70 fixed to the external support structure TO, fixed to the ground, of an oscillating table in which the crystalliser holding device is housed. In this first variant, the external manifold is constituted by a ring-shaped chamber 70 fed with a pressurised cooling fluid, generally untreated water, by tubes 80. in the internal "partthereof, said.ring-shaped chamber70 is provided with a plurality of holes 100, suited to generating jets of said fluid towards the rollers 50 at the foot and the continuous ingot.
A second variant of this second embodiment, illustrated in Fig. 4b, on the other hand, provides tubes SO' that feed ring-shaped manifolds 90 that in turn feed spray nozzles 200, arranged in correspondence wth the rollers 50 at the foot of the crystalliser 30.
Advantageously, this second embodiment of the crystalliser holding device in its two variants makes It possible to obtain a greater compactness of the manifold 7, a reduction of the overall dimensions and a greater constructive simplicity of the crystalliser holding device, as fewer seals are needed, and a lower overall weight of the cartridge-crystalliser complex.
This secondary cooling system, in both the variant with spray nozzles and in the perforated chamber variant, is fixed to the fixed support structure of the oscillating

table and therefore it does not osciiiaie with the rest of the ingot mould, thus reducing the inertia of the mobile part made to oscillate by the table. A further advantage is represented by the fact that such external secondary cooling system is not replaced together with the crystalliser and can be used for all cast sections.
A further advantage of the crystailiser holding device of the invention derives from the fact of having a compact configuration such as to be housed with a simple operation in a suitable oscillating table, globally indicated with reference 1, illustrated in Figures 1 and 2. In fact, it is possible to extract by means of an appliance the single block of the crystaliiser holding device comprising the ring-shaped manifold 7 and the crystalliser 30, provided with both primary and secondary or just primary cooiing ducts, simply by acting on the hydraulic brackets 15.
These hydraulic or mechanical oscillation actuation means 3 are connected to the ground with interlocking leaf-springs and are connected at the other extremity thereof to the structure 20, as a mobile element, again with an interlocking leaf-spring. As in such an oscillation control there is a complete absence of bearings, pins, joints or other mechanical organs, one eiiminates the clearances of such components, which are notoriously suuject to wear, entailing irecjuent maintenance operations.
In order to avoid deviations of the crystalliser 30 from the desired trajectory, preferably that along the casting direction or axis X defined by the same crystailiser, there are provided elastic guiding elements 11, 11', 12, 12' of the support structure 20 housing in the centra! cavity thereof the crystaliiser holding device 34, closely fastened thereto by means of hydraulic brackets 15 or other mechanical means.
Such guiding elements 11, IT, 12, 12', for example in the form of interlocking round or flattened elastic bars, are arranged as illustrated, for example, in figures 1 and 2. In this preferred embodiment, such elastic guiding elements advantageously comprise four pairs of first elastic bars 11, 1V and four pairs of second elastic bars 12, 12'. The number of the pairs of first and second bars may also be different but is in any case an even number. The four pairs of the first elastic bars 11, 1T are arranged in pairs respectively on

two first vertical planes parallel to one another snd to the casting axis X and equidistant from said axis. Similarly, the four pairs of the second elastic bars 12, 12' are arranged in pairs respectively on two second vertical planes parallel to one another and to the casting axis X and equidistant from sad axis; said second planes-being substantially perpendicular to said first planes. The bars 11, 11', 12, 12', such as for example round bars or bars of other substantially flattened shape sections, such as, for example, rectangular, are fixed at a first extremity thereof to the second support structure 20 of the crystalliser holding device 34, i.e. to the mobile part of the oscillating table, and at a second extremity thereof they are fixed to the outer support structure 10. The systems for fixing the bars to the support structure 20 are constituted, for example, by brackets welded to said structure that present passing holes in which the bars are inserted; the ends of such bars are threaded and the locking thereof on the brackets takes place by means of nuts. The fixing of the bars to the outer support structure 1.0 can be performed with similar systems, i.e. by means of introduction of the threaded end of the bars into the thickness of the structure and locking thereof with nuts.
On each of these first and^second vertical planes, the distance between the upper pair of bars, arranged In the proximity of the crystalliser head, and the lower pair, arranged in the proxtmity of the crystalliser feet, is advantageously the same. The first elastic bars 11, 11' are parallel to one another, as are the second elastic bars 12,12'.
The elastic bars are arranged so as to be stiff to bending in the transverse directions with respect to the casting or oscillating direction X and flexible in direction X only.
One embodiment provides the use of leaf-springs or similar springs as elastic guiding elements of the crystalliser 30.'
Advantageously, the fact that on each of said first and second vertical planes, each of the elastic bars of each pair presents the first end fixed to the mobile part of the table and the second end fixed to the fixed part in the opposite way with respect to the corresponding ends of the Immediately adjacent bar of the same pair, together with the fact that the an^angement of the pairs of corresponding bars respectively on the first and second planes is asymmetrical with respect to the
n.

casting direction or axis X (as siiown for example by observing tlie bars 12, 12' in Fig. 1 or in Fig. 2), mal<:es the osciliation of the crystailiser 30 of the invention only possible along the direction of casting axis X.
in fact, such configuration of the pairs of elastic bars 11, 11', 12, 12' makes it possible to contrast each torsion moment that could occur parallel to the casting direction X. According to the sense of this torsion moment, half of the bars will be subject to traction, acting as tie rods, whereas the other half will be subject to compression, acting as struts.
The use of simplified elastic guiding elements and the particular configuration thereof thus allow a very high crystailiser guiding precision and a considerable reduction in the oscillation marks on the cast product.
The crystailiser holding device of the invention also advantageously provides the housing of curved crystailisers. In these cases, such crystailiser holding device can be housed with a simple operation inside the second support structure 20 of an appropriate oscillating table illustrated in Fig. la.
In this case, the oscillating table advantageously provides on the two first vertical planes two pairs of first elastic guiding elements 35, 35', for example in the form of interlocking rounded or flattened elastic bars, each pair having a predetermined inclination, ecjuai in ausoiute va^ue uut opposite in sign to the otner pair, vvith respect to a horizontal piane perpendicular to casting-direction X. On each first vertical plane, the two pairs of first elastic bars 35, 35' respectively have an ideal intersection point 37 that defines a common centre of rotation. The two centres of rotation are arranged on an axis of rotation lying on said horizontal plane and petpendicular to casting direction or axis X in order to aliow the oscillating movement of the table following a circumference arc corresponding to a predetermined radius of curvature.
In general, the pairs of the first elastic bars 35, 35' on each first vertical plane are not parallel to one another, they may present different inclinations to one another and their ideal intersection point defines a common ideal centre of rotation, Similarly to the first embodiment, there are provided four pairs of second elastic bars 36, 36', arranged in pairs respectively on two second vertical planes parallel to one another and to the casting axis X, and equidistant from said axis; said second planes being substantially perpendicular to said first planes. The second

elastic bars 36, 36', unlike the first bars 35, 35', are arranged horizontaily and are all parallel to one another.
Also in this embodiment of the table, the fact that on each of said first and second vertical planes each of the elastic bars of each pair presents the first end fixed to the mobile part of the table and the second end fixed to the fixed part in the opposite way with respect to the corresponding ends of the immediately adjacent bar of the same pair, together with the fact that the "arrangement of the corresponding pairs of bars respectively on the first and second planes is asymmetrical with respect to the casting direction or axis X, makes the oscillation of the crystalliser 30 only possible along the direction of the casting axis X, following a circumference arc corresponding to a predetermined radius of curvature, substantiaiiy equal to the radius of curvature of the curved crystaliiser or of a different value.
In both embodiments of the oscillating table described above, the use of significantly simplified elastic guiding elements and the particular configuration thereof thus allow a very high crystalliser guiding precision and a considerable reduction in the oscillation marks on the cast product.
The oscillating table comprising the crystalliser holding device of the invention, thanks to the improvements described above, also allows a greater compactness and constructive simplicity and an operation at oscillation frequencies of overSHz, higher than the normal frequencies equal to 4H2. in the case of the production of cast products, for example those made of special steels and quality steels, there is provided the use of an electromagnetic stirrer 4, arranged between first 10 and second 20 support structure and advantageously protected from heat load. Lastly, given the compactness and the lower weight of the crystalliser holding device, it is not necessary to provide further elastic means, for example compression or air or leaf-springs, with the function of lightening the crystalliser holding device and the mobile stoicture of the table through a better weight distribution.
The particular embodiments described herein do not restrict the scope of this application, which covers all the invention variants defined in the claims.

New claims
1. Crystalliser holding device (34) for casting steel products such as billets, blooms
and slabs from liquid steel, comprising;
- a tubular crystalliser (30) defining a longitudinal casting direction (X) provided with a plurality of longitudinal channels (5) for the passage of a first cooling fluid,
- a substantially ring-shaped casing (7) arranged at a first end of said tubular crystalliser (30) comprising a first chamber (31) for feeding the first cooling fluid into said plurality of longitudinal channels (5), characterised in that
- the tubular crystalliser (30) is monolithic and the longitudinal cooling holes 5 are made in the thickness thereof, whereby said longitudinal channels (5) are very close to the inner walls (6) of said crystalliser (30) and provide a primary cooling of the liquid steel,
- said first cooling fluid is introduced into said longitudinal-channels (5) from the top towards the bottom through said first chamber (31) of the ring-shaped casing (7),
- the inner wall of said crystalliser holding device (34) and the external wali of the crystalliser (30) provides at least one first re-ascent duct (5') for-the first cooling fluid,
- said first duct (5'} communicating with a second chamber (32) for recycling the first fluid provided in said casing (7),
- said longitudinal channels (5) are in communication with said first duct (5') in correspondence with a second end in correspondence of the foot of the tubular crystalliser (30).
2. Crystalliser holding device according to claim 1, wherein said plurality of
longitudinal channels (5) is communicating with said at least one first duct (5') in
correspondence with a second end of the tubular crystalliser (30).
3, Crystalliser holding device according to claim 2, wherein there are provided hydraulic brackets (15) for the fixing of said device (34) to a mobile part (20) of an oscillating table(i),
4, Crystalliser holding device according to claim 3, wherein the tubular crystalliser (30) has a section, on a plane perpendicular to the casting direction (X), of a circular or square or rectangular shape.

5. Crystaliiser holding device according to one of the claims 1 to 4, wherein there is provided at least one second (5") communicating with a third chamber (33) for feeding the second fluid provided in said casing (7).
6. Crystaliiser holding device according to claim 5, wherein said second duct (5") is suited to feeding with the second fluid spray means (40), for a cooling arranged at the second end of the tubular crystaliiser (30).
7. Crystaliiser holding device according to claim 6, wherein the plurality of
longitudinal channels (5) and said at least one first and second ducts (5', 5") are
arranged parallel to one another and to the casting direction (X).
8. Crystaliiser holding device according to claim 7, wherein said first, second and
third chambers (31, 32, 33) are ananged inside the casing (7) in a concentric way
with respect to the casting direction (X).
9. Crystaliiser holding device according to one of the claims 1 to 4, wherein in
correspondence with the second end of the tubular crystaliiser (30) there is
provided at least one manifold (70, 90), external to the crystaliiser and fixed to a
fixed frame housing the crystaliiser holding device (34), for the passage of a
pressurised second cooling fluid, said external manifoid being suited to being fed
with the second cooling fluid by tubes (80, 80').
10. Crystaliiser holding device according to claim 9, wherein said external manifold
comprises a ring-shaped chamber (70) provided with a plurality of hoies (100)
suited to generating jets of said second fluid for a cooling arranged at the second
end of the tubular crystaliiser (30).
11. Crystaliiser holding device according to claim 9, wherein there are provided
erne or more manifolds (90) suited to feeding with the second fluid spray means
(200), for a cooling arranged at the second end of the tubular crystaliiser (30).
12. Crystaliiser holding device according to claims 10 or 11, wherein the plurality
3f longitudinal channels (5) and said at least one first duct (5') are arranged