EP1133372B1 - Tilting tank for processing liquid metal and device for sealed connection with fixed chute - Google Patents

Abstract

A tank for liquid metal processing tilting about an axis and fed by a fixed chute and pouring the liquid metal into a fixed evacuating chute. The tank includes at least a passage hole for supplying, discharging, or emptying the liquid metal arranged in one of its walls and extended by a mobile nozzle integral with the tank. At least the fixed evacuation chute merges with the tilting axis and the nozzle. Further, the fixed chute is assembled together by a linking device articulated in rotation about the tilting axis.

Description

TECHNICAL AREA

The invention relates to a tilting tank for the treatment of liquid metal, typically for gas treatment or filtration of aluminum or liquid magnesium or their alloys, and its sealed assembly device with fixed chutes serving to feed or evacuate said liquid metal from the tank.

STATE OF THE ART

A liquid metal tank used for its treatment by gases or for its filtration or simply at its standby storage, has a capacity generally not exceeding 3 tonnes and includes liquid metal feed and output devices. Says it liquid metal enters and leaves the tank continuously, however it is regularly necessary to partially or completely drain the latter by tilting around a horizontal axis at an angle typically between 30 ° and 90 °. In more than that, the tank can be fitted with a special drain hole located in its lower part.

The liquid metal outlet device comprises an orifice, or tap hole, drilled usually at the top of one of the walls of the tank, extended by a pouring spout pouring the liquid metal into a fixed discharge chute. The device supply of liquid metal from a fixed chute is generally the same so. Typically the tank is a rectangular parallelepiped and the tilting axis parallel to its great length. It is essential that the articulated connection between the spout integral with the tank and the fixed chute remains tight against liquid metal at high temperature, despite repeated heating and cooling cycles of installation.

It is known to pour liquid metal into a fixed chute perpendicular to the axis horizontal tilting. The latter, usually located at the height of the poured, is then deported outside the tank and passes through the end common to the spout and chute arranged in the extension of one another.

When the tank is tilted, we see that the outlet spout of said tank and the chute fixed make a variable angle and that the connection between these two elements must be articulated and waterproof. To make this joint watertight, it is known to produce a metal knee cap wrapping the ends of the spout and fixed chute and lining the internal face of said toggle with a lining, may be a graphite-based braid, to ensure sealing with the faces external of the spout and the chute. Thus, during the tilting of the tank, its spout outlet moves by rubbing tightly on the lining of the toggle.

When tilted, the tank equipped with such an arrangement has a large footprint, especially when the tilt angle is 90 °, this space being due to the fact that the tilting axis passes at the end of the spout. In addition, metal can freeze in the articulated device, in particular between the knee, beak and chute, which complicates and particularly annoys the maintenance or dismantling operations.

There are also known melting furnaces and liquid metal storage of large capacity (several tens of tonnes) tilting around a horizontal axis and pouring the liquid metal into a fixed chute located in the extension of said axis, the tilting angle of which does not generally exceed 10 to 20 °. In that case, a sealed rotary connection between the pouring spout integral with the oven, also located on the tilting axis, and the fixed chute of semi-circular cross section consists of fit and adjust the spout integral with the tank, also having a straight section semicircular with slightly smaller diameter, and to slide in rotation the two semicircular parts relative to each other using a gasket sealing, often based on graphite, located between them.

Such a device can only be used for small tilt angles due to the fact that the braid is driven as soon as the tilt angle becomes a little important. Thus, this device is not applicable to treatment tanks, in especially those who tilt with large angles. In addition, it is difficult to obtain a good seal because said two parts embedded one inside the other are expand differently diametrically, that the troughs easily deform during the many thermal cycles that they undergo and that the clamping force of the braid is not adjustable. In addition, there are great risks of blocking the device in because of the metal which can slip and freeze in the gap between the spout and the chute.

The plaintiff has thus sought to avoid the above drawbacks and to point a tilting treatment tank of reduced tilting size and having simultaneously an articulated connection device, between the spout integral with the tank and the fixed chute, perfectly watertight while being simple in design and of use (adjustment, maintenance, disassembly, cleaning) and without the said device could be the cause of freezing (solidification) of liquid metal.

DESCRIPTION OF THE INVENTION

The invention is a liquid metal treatment tank tilting around an axis, fed by a fixed chute and discharging said liquid metal into a fixed chute evacuation, said tank comprising at least one through hole for feeding, removing or emptying the liquid metal practiced in one of its walls and extended by a so-called movable spout secured to the tank, characterized in that at least the axis of the fixed discharge chute coincides with the tilting axis.

Usually the axis of the feed chute is also coincident with the axis tipping. It is particularly advantageous to practice this arrangement for tanks tilting at an angle greater than 30 ° and up to 90 °.

In general, the tank is at least approximately rectangular parallelepiped, its walls which may have a slight draft, and the tilt axis is parallel to its great length, that is to say parallel to the large walls and perpendicular to the small.

Said tilting axis preferably passes through an upper angle of said small walls; in this case it is confused not only with the axes of the fixed chutes and mobile pouring or feeding spouts but also with those of the casting or feeding. But it can very well be located in another place of the tank or even deported outside the tank; in this case it is still confused with axes of fixed chutes and movable spouts.

According to the invention the ends of the movable spouts and the fixed section trunks circular straight, aligned on the tilt axis, are connected by a link articulated in rotation around said axis, tight against liquid metal, capable of rotate at an angle greater than 30 ° and up to 90 ° without losing its seal and thus allowing the tank to be partially or totally drained.

• une bride d'adaptation assujettie à l'extrémité du bec, centrée sur l'axe de basculement, comportant une portée de joint circulaire dont le plan est perpendiculaire audit axe ;
• une bride de liaison assujettie à l'extrémité de la goulotte fixe, centrée sur l'axe de basculement, comportant une portée de joint circulaire, dont le plan est perpendiculaire audit axe, faisant face à la précédente et coopérant avec elle ;
• au moins un joint résistant à la chaleur et au métal liquide situé entre les deux portées ;
• un dispositif de serrage, prenant éventuellement appui sur une pièce fixe, permettant de régler et de maintenir le serrage des brides l'une par rapport à l'autre pour assurer l'étanchéité de la liaison tout en laissant lesdites deux brides pivoter l'une par rapport à l'autre.

Said device articulated in rotation according to the invention comprises

• an adaptation flange secured to the end of the spout, centered on the tilting axis, comprising a bearing surface of a circular joint whose plane is perpendicular to said axis;
• a connecting flange secured to the end of the fixed chute, centered on the tilting axis, having a bearing surface of a circular joint, the plane of which is perpendicular to said axis, facing the preceding one and cooperating with it;
• at least one heat and liquid metal resistant seal located between the two surfaces;
• a clamping device, possibly supported on a fixed part, making it possible to adjust and maintain the clamping of the flanges relative to one another to ensure the tightness of the connection while leaving said two flanges pivot one compared to each other.

There are preferably two graphite-based seals, one attached to the seat of each bridle, rubbing one over the other.

The movable spout and the fixed chute being in the extension of each other so that the bearing surfaces of the facing joints correspond perfectly, it is advantageous to have centering means cooperating with each other on each of the flanges and can constitute a centering device.

Thus, one of the flanges may have a cylindrical protuberance, at the end of which can be the joint surface; this circular protuberance like the flange is intended to engage with gentle friction in a corresponding housing located on the other flange and at the bottom of which can be the other bearing surface making opposite that of the first flange. We see that the nesting of these two parts ensures centering the joint surfaces.

To obtain liquid metal tightness while having a friction force adapted to allow rotation of one flange with respect to the other, it only remains more than pressing the two seals against each other using the clamping device. To prevent the fixed chute from being entrained during the rotation of the spout, it is advantageous to reinforce its immobilization near the connecting flange, by example using reinforcement bars integral with a frame.

The tightening device may include threaded tie rods bearing on the one hand on one or more supporting parts integral with the frame, fixed or preferably maneuverable, and on the other hand on the connecting flange, by means of elastic parts, by example of springs or curved washers of the so-called "belleville" type. Nuts adjust the clamping force by compressing the parts more or less elastic. The elastic parts also make it possible to maintain the tightness during thermal cycles by collecting expansions.

We see that such a device, where the expansions occur in the axis, allows to to overcome recurrent or endemic deformations due to thermal cycles suffered by the assembly during stops and restarting of the tank, and obtaining the desired tightness by avoiding any untimely leakage or freezing of liquid metal which could interfere with tank operations. Similarly to disassemble the device by in view of its cleaning or maintenance (for example: changing the seals), it just move the two flanges apart.

To facilitate disassembly, it is also possible to extend the connecting flange by a portion of fixed trunking subject to the fixed trough proper using a rigid fixing device (for example using flanges integral with the chute and of the trunking portion, bolted together), watertight, easily removable and accessible and to rest, the assembly (portion of fixed chute, connecting flange, clamping device) on a mobile carriage also carrying the support frame of the clamping device. For disassembly, it will suffice to uncouple the chute fixed portion of the chute and spread it with its spout connecting flange mobile equipped with its adapter flange after releasing the clamping device.

The flanges are generally made of steel or refractory cast iron; inside the portion of fixed chute can be coated with the same refractory product as that of the spouts, liquid metal troughs or tank.

The device according to the invention applies to the connection of the liquid metal tank also well with its outlet chute than with that of supply. When it applies to two, the latter are located on the same axis, as has already been said.

The invention also relates to liquid metal tanks comprising one or more articulated connection devices and methods using the tanks or the so-called devices according to the invention. The processes are in particular filtration or gas treatment of liquid metals such as aluminum, magnesium or their alloys.

Figure 1 illustrates the invention and shows a view of a liquid metal tank of which the tilt axis passes through the upper part of one of its walls.

FIG. 2 represents a profile view of an articulated link in rotation mounted on a liquid metal tank of the type of that of FIG. 1.

FIG. 3 illustrates a profile view of the preferred embodiment of the connection articulated in rotation according to the invention.

Figure 1 shows the installation of a passage hole (5) for pouring, emptying or the supply of liquid metal and the spout (7) extending it on a small wall (2) of the tank (1). The through hole (5) is located at the top of said tank, near a large wall (25) (sectional view) perpendicular to the small wall (2); axis tilting (6) passes through its center and is parallel to said large wall (25). We sees that, thanks to this arrangement and to the sealed articulated connection device according to the invention, it is easily possible to completely empty the tank by tilting it in the direction of the arrow (24), the need for space to perform this operation being minimized.

In FIG. 2 we see in (1) a tank of parallelepipedal liquid metal with a small wall (2) with a slight draft, covered internally with a refractory material (2a), and a cover (3) also internally covered with a refractory material (4). At the top of the tank (1) there is a passage (5) for pouring, draining or feeding the liquid metal. The tank is tilting about the tilting axis (6) passing through said through hole (5). This the latter is extended by a movable spout (7) integral with the tank (1) and which pivots with she; it is coated internally with a refractory material (8).

The adjustable tightening of the seals (12, 13) can be ensured by threaded tie rods (19) bearing on a fixed part (20) secured to a frame (21), by means a spring (22) whose crushing is regulated by nuts.

• une bride d'adaptation (10, 10a, 10b, 10c) assujettie à l'extrémité du bec (7, 8), centrée sur l'axe de basculement (6) et comportant une portée de joint circulaire perpendiculaire au dit axe (6) ;
• une bride de liaison (15, 15a, 15b) assujettie à l'extrémité de la goulotte fixe (17, 18), centrée sur l'axe de basculement (6) et comportant une portée de joint circulaire, perpendiculaire au dit axe (6), faisant face à la précédente et coopérant avec elle ;
• au moins un joint (12, 13) résistant à la chaleur et au métal liquide situé entre les deux portées ;
• un dispositif de serrage (19, 19a, 22, 22a, 22b 22c) permettant de régler le serrage des brides (10, 10a, 10b, 10c, 15, 15a, 15b) l'une par rapport à l'autre pour assurer l'étanchéité de la liaison tout en laissant lesdites brides (10, 10a, 10b, 10c, 15, 15a, 15b) pivoter l'une par rapport à l'autre.

As illustrated in FIGS. 2 and 3, the sealed connection device for liquid metal, articulated in rotation about an axis (6) and allowing the tilting of a tank (1) of liquid metal, comprises:

• an adaptation flange (10, 10a, 10b, 10c) secured to the end of the spout (7, 8), centered on the tilting axis (6) and comprising a bearing surface of a circular joint perpendicular to said axis (6 );
• a connecting flange (15, 15a, 15b) secured to the end of the fixed chute (17, 18), centered on the tilting axis (6) and comprising a bearing surface of a circular joint, perpendicular to said axis (6 ), facing and cooperating with the previous one;
• at least one seal (12, 13) resistant to heat and liquid metal located between the two surfaces;
• a clamping device (19, 19a, 22, 22a, 22b 22c) for adjusting the clamping of the flanges (10, 10a, 10b, 10c, 15, 15a, 15b) relative to each other to ensure the sealing of the connection while leaving said flanges (10, 10a, 10b, 10c, 15, 15a, 15b) pivot relative to one another.

The connecting device according to the invention advantageously comprises a device for centering (11, 11a, 14, 14a) of the flanges (10, 10a, 10b, 10c, 15, 15a, 15b) one by compared to each other. This centering device can comprise, on one of the flanges (10, 10a, 10b, 10c, 15, 15a, 15b), a cylindrical protuberance (11, 11a) engaging gentle friction without a corresponding housing (14, 14a) located on the other flange (10, 10a, 10b, 10c, 15, 15a, 15b). According to the variant of FIG. 2, one of the ranges of seals can be found at the end of the protrusion (11), the other seal surface is located at the bottom of the housing (14), so that the two joint surfaces are face each other. According to the variant of FIG. 3, the joint surfaces are provided at the end of specific protrusions (15b, 10b) of the flanges (10a, 10b, 10c, 15a, 15b), said bearing surfaces being arranged so that they face each other.

According to the first embodiment of the invention, the adjustable clamping device includes threaded tie rods (19) bearing on one hand on one or more parts fixed support (20), preferably integral with a frame (21) and on the other hand on a flanges (10, 15), by means of elastic parts or a spring (22), nuts to adjust the crushing and, therefore, the clamping force.

According to the second embodiment of the invention, the adjustable clamping device includes a protrusion (22c) on one of the flanges (10, 10a, 10b, 10c, 15, 15a, 15b), an annular flange (22b) and means for adjusting the clamping (19a, 22a), such as bolts (19a) and "belleville" type washers (22a). This variant further simplifies the opening and dismantling of the connecting device.

The spout (7) may have at its end a counter flange (9) on which is fixed sealingly the adapter flange (10) having a protrusion (11) cylindrical. According to a variant of the invention, on the joint surface located at the end of said protuberance (11) is placed the seal (12) preferably based on graphite. This seal (12) is applied against the corresponding seal (13) placed on the seal surface located at the bottom of the cylindrical housing (14) forming part of the flange link (15) and cooperating with the protuberance (11) to center the device. according to another variant of the invention, the flanges (10, 10a, 10b, 10c, 15, 15a, 15b) can have several separate parts which are preferably fixed to each other, for example, using rotating stop pins (26, 27) or fixing means (28). The rotating stop pins (26, 27) can be welded to the flanges (10b, 15b) corresponding and specific housings provided in the flanges (10a, 15a) corresponding.

The connecting flange (15, 15a, 15b) is fixed with a counter flange (16) on a removable fixed chute portion (17), located in the extension of the main body fixed chute (18). In (23) we see a sealed coupling device between the main body (18) and the removable portion (17) of the fixed chute.

It may be advantageous to provide a seal (29), heat and metal resistant liquid, between the connection flange (15, 15a, 15b) and the counter flange (16).

Claims (16)

1. Vessel (1) for treating liquid metal, tilting about an axis (6), fed by a fixed trough and pouring said liquid metal into a fixed evacuation trough (17,18), said vessel comprising at least one passage hole (5) for supplying, discharging or emptying the liquid metal, arranged in one of its walls (2) and extended by a so-called mobile spout (7, 8) integral with the vessel, characterized in that at least the axis of the fixed evacuation trough (17, 18) merges with the tilt axis (6).
2. Vessel according to claim 1, characterized in that the vessel (1) is a rectangular parallelepiped, the horizontal tilt axis (6) being parallel to its greater length, and is either offset outside the vessel (1) or is preferably positioned at its upper part.
3. Vessel according to either of claims 1 or 2, characterized in that the tilt angle lies between 30° and 90°.
4. Vessel according to any of claims 1 to 3, characterized in that at least one end part of the fixed trough (17, 18) and of the mobile spout (7, 8) have a circular section and are connected by a device articulated in rotation about the tilt axis (6) sealed against liquid metal.
5. Connection device sealed against liquid metal, articulated in rotation about an axis (6) to enable, in particular, tilting of a vessel (1) of liquid metal, such as described in any of claims 1 to 4, about axis (6), between firstly a so-called mobile spout (7,8) integral with vessel (1), aligned along said axis (6), and secondly a fixed trough (17, 18) intended to circulate the liquid metal, also aligned along said axis (6), the said mobile spout (7, 8) and fixed trough (17, 18) each having at least one end part with a circular section, characterized in that it comprises:

   an adapter flange (10, 10a, 10b, 10c) secured to the end of spout (7, 8), centred over the tilt axis (6) and comprising a circular seal bearing perpendicular to said axis (6);

   a connection flange (15, 15a, 15b) secured to the end of the fixed trough (17, 18) centred over the tilt axis (6) and comprising a circular seal bearing, perpendicular to said axis (6) facing and co-operating with the preceding bearing;

   at least one seal (12, 13) resistant to heat and liquid metal, positioned between the two bearings;

   a clamp device (19, 19a, 22, 22a, 22b, 22c) optionally supported by a fixed part (20), used to adjust clamping of flanges (10, 10a, 10b, 10c, 15, 15a, 15b) relative to one another, and to ensure sealing of the connection while allowing said two flanges (10, 10a, 10b, 10c, 15, 15a, 15b) to pivot relative to one another.
6. Device according to claim 5, characterized in that flanges (10, 10a, 10b, 10c, 15, 15a, 15b) comprise a centering device (11, 11a, 14, 14a) for their centering relative to one another.
7. Device according to claim 6, characterized in that the centering device comprises on one of the flanges (10, 10a, 10b, 10c, 15, 15a, 15b) a cylindrical projection (11, 11a) which slide fits into a corresponding housing (14, 14a) positioned on the other flange (10, 10a, 10b, 10c, 15, 15a, 15b).
8. Device according to claim 7, characterized in that one seal bearing is located at the end of the cylindrical projection (11) and another seal bearing is located in the bottom part of housing (14) so that the two seal bearings face one another.
9. Device according to claim 7, characterized in that it comprises two specific projections (15b, 10b) of flanges (10a, 10b, 10c, 15a, 15b) a seal bearing being placed at the end of each one, arranged so that the two seal bearings face one another.
10. Device according to any of claims 5 to 9, characterized in that it comprises two seals (12, 13), one on each bearing.
11. Device according to any of claims 5 to 10, characterized in that the flanges (10, 10a, 10b, 10c, 15, 15a, 15b) are in steel or refractory cast iron and/or the seals (12, 13) are graphite-based.
12. Device according to any of claims 5 to 11, characterized in that the adjustable clamp device comprises screw tie rods (19) supported firstly by one or more fixed support parts (20), preferably integral with a frame (21), and secondly by one of flanges (10, 15), via elastic parts (22), nuts being used to adjust the clamping force.
13. Device according to any of claims 5 to 11, characterized in that the adjustable clamp device comprises a projection (22c) on one of flanges (10, 10a, 10b, 10c, 15, 15a, 15b), a ring flange (22b) and clamp adjusting means (19a, 22a), such as bolts (19a) and washers of "belleville" type (22a).
14. Device according to any of claims 5 to 13, characterized in that the fixed trough comprises a removable portion of fixed trough (17).
15. Process using the vessel of any of claims 1 to 4, or using the device of any of claims 5 to 14.
16. Process according to claim 15, characterized in that it is used for the gas or filtration treatment of liquid aluminium, magnesium or their alloys.

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