EP0123121B1 - Feeding equipment for feeding a steel melt to continuous casting machines with mould walls movable in the casting direction - Google Patents

Abstract

In order to be able to manipulate a feeding device with which molten steel is introduced into a twin-belt caster without ingress of air in preparation for the casting process and to carefully align the feeding device and the caster to the required extent, the feeding device includes a pouring body which is mounted in its own carriage so as to be rotatable about a horizontal pivot axis, and a separately movable tundish which is connected with the pouring body via a ball joint which forms the point of separation in that the ball socket of the ball joint and the ball pivot of the ball pivot are each respectively associated with either the tundish or the pouring body. The pouring body can be arrested in the manner of a rocker in different sloped positions and can be laterally displaced in a direction transverse to its longitudinal extent. The associated mode of operation of a feeding device equipped with a pouring body and tundish according to the apparatus of the invention comprises initially moving the spout of the pouring body between the mold walls of the twin-belt caster a few millimeters further than that corresponding to the casting position, thereafter moving the tundish in the direction toward the twin-belt caster and arresting the tundish in its casting position, and finally setting the pouring body back against the connecting surface of the tundish so as to establish an outwardly closed connection.

Description

The invention relates to a feed device for introducing molten steel into continuous casting machines with mold walls moving in the casting direction, with a tubular, closed casting body which is movable and height-adjustable with respect to the continuous casting machine, via whose mouthpiece protruding between the mold walls, a sealing gap can be produced therewith and preceded by a front container, whereby this is adjustable in height and at least the latter can be moved from the two parts which can be connected to one another via the casting body - continuous casting machine and front container.

According to the knowledge available to date, steel, for example with a casting cross section of approximately 70 x 180 mm, can be cast at speeds of around 10 m / min. Only cast to the strand with casting machines that have moving mold walls. Attempts to process steel at higher casting speeds in such continuous casting machines have, however, not yet led to casting products of sufficiently good metallurgical quality.

From DE-AS-30 09 189 which forms the preamble of claim 1, a cooperating with a rigid casting mold supply device for introducing molten steel is known, the tubular casting body is immovably connected to a header tank and can be moved with respect to the continuous casting mold as well as height adjustable. The sealing of the annular gap between the back and forth, d. H. temporarily also in the casting direction moving casting mold and the pouring body protruding into it is brought about by generating induction forces by means of a magnetic coil which surrounds the casting mold on the outside and is also effective in its initial section. The disadvantage of the known design is that it can only be aligned with respect to the continuous casting mold by moving and adjusting the height of the heavy front container.

In the subject of DE-OS-17 58 960, a front container with a rigid nozzle is connected via a ball joint to a rigid casting mold which is rigid in itself. The movable part of the ball joint forms a short casting body in the form of a spherical section, which is supported via its convex surface in the concave counter surface of the connecting piece. The end face of the spherical section facing away from the front container is sealingly held against an annular plate which at the same time forms the immovable mouthpiece of the spherical section. Screws attached to the header serve as pressure elements. The disadvantage of this known proposed solution is that the only compensating movement is a rotary movement between the front container and the continuous casting mold. During the casting process, however, the header warms up more than the continuous casting mold, i. H. the two parts mentioned move against each other in the vertical direction, which would make an automatic height adjustment necessary. However, this is not provided and, because of the short construction of the pouring body, is also not feasible.

The invention is based on the knowledge known per se that flawless cast products can only be achieved by means of continuous casting machines in the form of double belt casting machines if the molten steel can be introduced between the moving mold walls of the continuous casting machine without outside air.

It must be ensured that the molten steel cannot leave the continuous casting machine in the opposite direction to the casting direction and that damage to the mold walls and the mouthpiece of the pouring body is avoided despite sufficient tightness.

The object of the invention is to develop a feed device for introducing molten steel from a header tank into a continuous casting machine in the form of a double belt casting machine (twin belt casting machine) with casting belts arranged in pairs and adjoining link walls in the form of insulating block chains. To avoid freezing at the start of casting, the feed device should have a readily preheatable pouring body, which can also compensate for changes in dimensions occurring on the front container and which, moreover, can be moved with respect to the double belt casting machine in such a way that geometric conditions exist between the mouthpiece and the mold walls surrounding it even during a prolonged casting process can be maintained, which ensure a secure seal between the mold walls and the mouthpiece of the pouring body: In particular, it should be possible to maintain a tight sealing gap that is as constant as possible between the parts that are moved relative to one another.

The object is achieved by a feed device which has the features of claim 1. Thereafter, the pouring body of the feed device, which is rotatably held about a horizontal pivot axis and is also laterally adjustable transversely to its longitudinal extent, is designed with its own carriage as a pouring unit, which can be moved separately from the front container and from the continuous casting machine in the form of a known double-belt casting machine with mold walls moving exclusively in the casting direction. According to a further feature of the subject matter of the invention, the casting body is on the front container a ball joint. connectable, the ball socket or ball pin forming a connecting surface each belonging to different parts, namely the front container and the casting body.

The invention thus conveys the teaching of moving the separation point between the two parts which can be moved relative to one another - namely the front container and the casting body of the feed device - into the ball joint. The possibilities of movement of the cast body with respect to its slide (i.e. the rotatability about a horizontal pivot axis and the lateral adjustability transversely to the longitudinal extent) enable an exact alignment with respect to the downstream double belt casting machine. After the casting body has been preheated from the side of its mouthpiece, it can be moved in the direction of the double belt casting machine in such a way that between the mouthpiece and the mold walls delimiting a casting cavity, a narrow sealing gap which is as constant as possible on all sides, normally in the order of 0.3 to 1 mm is present. In order to be able to heat the cast-in body, the front container can be moved by a vehicle receiving it, equipped with a drive and movable in a guide. The front container is preferably height-adjustable in that the vehicle has wheel sets supported by eccentric bushings on the vehicle frame.

The range of motion of the pouring unit with respect to the double belt casting machine and that of the attachment container with respect to the pouring unit is dimensioned such that the pouring body can be preheated from its mouthpiece and the attachment container can be preheated from its connecting surface by means of burners which can be moved in its area (claim 2); these can each be moved about a fixed axis into a working and a rest position via a swivel arm.

In a further development of the subject matter of the invention, the cast-in body is supported on its slide in the manner of a rocker by means of a weight compensation - preferably consisting of a buffer with a variable spring characteristic (claim 4) (claim 3). The support of the castor body, which is rotatable about the horizontal pivot axis, on the buffer forming a flexible abutment has the result that the mouthpiece can perform compensating movements in the vertical direction within the moving mold walls, thereby reducing the risk of damage to the parts which are moved relative to one another.

In order to facilitate the alignment of the casting body with respect to the double belt casting machine and to avoid damage when threading the mouthpiece, the casting body can be supported outside of its pivot axis on a lockable tilt eccentric arranged on the slide; furthermore, the casting body has on its underside a metallic centering part with bevelled side surfaces, via which it can be threaded between the lateral mold walls - which protrude beyond the other mold walls against the casting direction (claim 5). By lowering the pouring body by means of the inclination eccentric about its pivot axis, the pouring body is thus aligned with respect to its lateral position in that the metallic centering part automatically threads itself between the projecting lateral mold walls under the action of its bevelled side surfaces. Subsequently, the mouthpiece of the pouring body can be brought into the area of the casting cavity of the double belt casting machine without difficulty. The separation point between the front container and the casting body is preferably designed such that the latter has a connecting surface designed as a spherical socket (i.e. concavely curved) on the side facing the front container; the front container is accordingly equipped with a connection surface which is designed as a ball pin, d. H. is convexly curved. It has proven to be expedient to support the connecting surfaces forming the separation point against one another via a sealing compound made of plastic material (claim 6).

This sealing compound - which has a pasty state in the temperature range between about 1 100 to 1 500 ° C - makes it possible to let the steel melt run into the double belt casting machine shortly after the two connecting surfaces have moved together through the casting body; it is composed of the essential components Si0 ₂ , Al _z 0 ₃ , B _z 0 ₃ , CaO, Na ₂ 0 and K ₂ 0, ordered according to the size of the proportions (claim 7). A plastic sealant with the following composition is preferably used: Si0 ₂ - 60%; A1 ₂ 0 ₃ - 14%; B ₂ 0 ₃ - 10%; Ca0 - 7%; Na20-5% and K ₂ 0 -4%.

According to a further development of the subject matter of the invention, the ceramic inner lining of the casting body is supported on an external steel jacket by means of a thermal insulation layer designed as a spring element, so that it can perform compensating movements to a small extent with respect to the steel jacket (claim 8). The advantage achieved in this way can be seen in the fact that the mouthpiece of the casting body can adapt to any changes in height that occur during the casting process. These result from the fact that the attachment container suspended on cantilever arms adopts higher temperatures as the casting process progresses and its contact surface consequently drops, while the height of the slide and the pivot axis of the casting body remain unchanged.

Correct alignment of the pouring body with respect to the mold walls is required in order to be able to cast under pressure using the double belt caster. This means that the molten pool level in the front container is constantly kept at a level during the casting process which lies above the outlet cross section of the mouthpiece. Such a control of the melt pool level in the header tank has the advantage that a cast pool level control is not required within the double belt casting machine. Die casting presupposes that the sealing gap between the mouthpiece and the moving mold walls is kept as constant as possible, which is made possible by the invention.

The feed device according to the invention is particularly easy to handle for establishing a connection between the front container and the double belt casting machine if the mouthpiece of the casting body is first inserted somewhat lower than in the casting position between the mold walls of the double belt casting machine before the casting body - after the front container reaches its casting position has - is brought into the pouring position by resetting against the connection surface of the front container, forming an externally closed connection. The advantage of this procedure can be seen in the fact that the heavy front container is moved into its pouring position and held there before the coupling mentioned is carried out via the considerably lighter casting body - which is already threaded into the double belt casting machine.

The invention is explained in detail below with reference to the exemplary embodiments shown in the drawing.

• Figur 1 im Längsschnitt den prinzipiellen Aufbau einer Zuführeinrichtung mit einem Eingußkörper, der in der Gießstellung einen Vorsatzbehälter mit einer Doppelbandgießmaschine verbindet,
• Figur 2 stark schematisiert eine Seitenansicht einer Eingußeinheit, die im wesentlichen aus dem Eingußkörper und einem diesen aufnehmenden Schlitten aufgebaut ist,
• Figur 3 einen Schnitt nach Linie 111-111 in Fig. 2,
• Figur 4 einen Teilschnitt nach Linie IV-IV in Fig. 2,
• Figur 5 schematisch einen Längsschnitt durch eine Zuführeinrichtung in der Vorheizstellung und
• Figur 6 schematisch einen Längsschnitt durch die in Fig. 5 dargestellte Zuführeinrichtung in der Gießstellung.

Show it :

• 1 shows in longitudinal section the basic structure of a feed device with a cast-in body, which in the casting position connects a front container to a double belt casting machine,
• FIG. 2 shows a highly schematic side view of a pouring unit, which is essentially constructed from the pouring body and a carriage receiving it,
• FIG. 3 shows a section along line 111-111 in FIG. 2,
• FIG. 4 shows a partial section along line IV-IV in FIG. 2,
• Figure 5 schematically shows a longitudinal section through a feed device in the preheating position and
• Figure 6 schematically shows a longitudinal section through the feed device shown in Fig. 5 in the pouring position.

The feed device according to the invention with a tubular casting body 1 works together with an upstream header tank 2 (tundish), the melting space 4 of which is delimited by a multilayered side wall 3 and merges downwards into a floor stone 5 and then into a floor channel 6. This is delimited by three successive, firmly connected stones 7, 8 and 9, of which the latter two protrude towards the casting body 1 and a downstream double belt casting machine 10 (twin belt casting machine).

During the casting process, molten steel is fed from the front container 2, avoiding air access through the bore 5 'of the base stone 5. Above this a stopper rod 11 is held adjustable in height, which can close the bore 5 'or release it for the flow.

The front container 2 with the interchangeably attached stones 8 and 9 can be moved and adjusted in height via a driven vehicle (shown in FIGS. 5 and 6). The connection surface 9 'of the stone 9 facing the casting body 1 is designed as a ball pin, i. H. it is convexly curved.

The initial section 12 of the two-part casting body 1 has as essential components a ceramic inner lining 13 with a pouring hole 14 adjoining the floor channel 6, a heat insulating layer 15 surrounding the inner lining and a rectangular steel jacket 16 serving as a supporting element. The heat insulating layer 15 is designed as a resilient spring element.

On the front side of the initial section 12 facing the double belt casting machine 10 there is a mouthpiece 19 which tapers in the casting direction (arrow 18) and which is essentially composed of a thin metal jacket 17 and a ceramic inner lining 13 'with a partially tapering casting hole 14'. The metal jacket 17 preferably consists of a nickel-chromium compound with the essential constituents: 73% Ni, 20% Cr, 1% Co, 5% Fe, 1% Co and traces of Cu, Al, Ti, C (all in all 1 %).

The mouthpiece 19 protrudes with its end section and its outlet cross section 19 'between the mold walls of the double belt casting machine 10 which are moving in the casting direction and which consist of endless casting belts 20 or pairs (not shown) lying laterally adjacent to these continuous insulating block chains. The four mold walls mentioned delimit a rectangular casting cavity 21, the longitudinal axis of which - like the longitudinal axis 1 'of the casting body 1 - is inclined by 6 ° with respect to the horizontal; the inclination of the casting cavity 21 is provided in order to be able to empty the double belt casting machine. The movement of the casting belts 20 is indicated by arrows 20 '.

The ceramic inner lining 13 of the starting section 12 is formed on its side facing the front container 2 as a concavely curved connection surface 13 ", which as a ball socket forms a ball joint with the convexly curved connection surface 9 'of the stone 9 serving as a ball pin. The connection surface 13" forms with the Pad 9 ' a separation point via which the front container 2 and the pouring body 1 can be connected to one another with the interposition of a sealing compound 22 applied to the connecting surface 9 '.

The casting body 1 is rotatably held in a slide 24 with a housing 25 via a horizontal pivot axis 23 (see FIGS. 2 and 3). The pouring unit essentially formed from parts 1 and 24 is supported on a guide track (not shown) via a lateral guide (i.e. on the right in FIG. 3). The pivot pin 23 '(on the right in FIG. 3) of the pivot axis 23 is provided outside the area of the associated bearing bush 26 with a rectangular groove 23 "into which the adjustment head 27' of a side adjustment screw 27 engages with lateral play; this in turn is supported their threaded section in an adjustment housing 28 connected to the bearing bush 26. By turning the side adjustment screw 27 with respect to the adjustment housing 28, the cast-in body supported on the pivot axis 23 can be laterally displaced within the housing 25 and can be held in the desired lateral position, roughly adjusted with regard to the alignment of the mouthpiece (cf. FIG. 1) in the cold state with respect to the insulating block chains 20 ″ serving as lateral mold walls, which protrude against the casting direction over the mold walls 20 designed as casting belts. There is approximately one mm of freedom of movement for hot alignment.

To support the pouring body 1, this is laterally (cf. in particular FIG. 3) equipped with a rigidly attached rocker arm 29 which projects beyond the housing 25 to the left and which rests on an elastically supported buffer 30; this is movably supported in a housing 31 via a spring element in the form of a package 32 of disc springs. The biasing force of the spring element can be increased or decreased by means of a biasing screw 33. The housing 31 is in turn attached to a side bracket 34 of the housing 25. By supporting the casting body 1 in the manner of a seesaw on the flexible buffer 30, the different forces which are caused by the different filling of the casting body are to be compensated for.

On the same side of the housing 25 (ie on the left in FIG. 3), as seen in the casting direction, behind the buffer 30 and below the pivot axis 23, an inclination eccentric 35 is attached, which as essential components comprises a support arm 36 held immovably, a bearing bush 37, an eccentric bushing 38 with an eccentric disk 38 'and a lever 39 which enables the adjustment of the inclination eccentric. The eccentric disk 38 'can be brought into contact with the already mentioned rocker arm 29.

By swiveling the lever 39 by hand or by means of an adjustment drive, for example in the form of a hydraulic cylinder, the inclined position of the casting body 1 with respect to the housing 25 can be changed continuously over a wide range. The position of the eccentric bushing 38 with respect to the support arm 36 can be secured in a simple manner in that a locking screw 40 extending through the parts 38 and 37 is braced against the support arm 36. The pouring body of the feed device according to the invention thus has an inclination adjustment in addition to the buffer 30 to facilitate the threading process.

The position of the inclination eccentric 35 and the buffer 30 with respect to the housing 25 can be seen in particular from FIG. 2; in the pouring position, the mouthpiece 19 protrudes at an angle of 6 ° into the casting cavity 21 formed by the mold walls 20 and 20 ", the longitudinal axis 1 'of the casting body 1 coinciding with the longitudinal axis of the casting cavity.

The advantage of the described embodiment is that the pouring body 1 can be brought into a position beforehand by pivoting the lever 39, which enables the mouthpiece 19 to be threaded effortlessly. For this purpose, a metallic centering part 41 with finely machined, bevelled side surfaces 41 'is attached below the casting body 1. By lowering the pouring body 1 downward, the side surfaces 41 'come into the region of the projecting lateral mold walls 20 "and bring the pouring body 1 into the required lateral position, in which the centering part 41 finally lies between the mold walls 20". Subsequently, only the carriage 24 has to be moved in the direction of the double belt casting machine (i.e. to the right in FIG. 2).

For the sake of better understanding, the end edge of the ceramic inner lining 13 of the cast-in body 1 encompassing the concave connection surface 13 "is indicated as line 13" 'in FIG. 2. The pivot axis 23 is then - seen in the casting direction - in front of the end edge 13 '"and thus in front of the concave connection surface 13" shown in FIG. 1, which forms the ball socket of the ball joint. It is essential in this context that the center of the casting body 1 movable in the manner of a seesaw and the center of the ball of the ball joint are identical to one another.

In the embodiment according to FIGS. 5 and 6, the pouring body 1, shown in simplified form, is movably connected to the slide 24 via the housing 25 with the horizontal pivot axis 23, which in turn is supported on a stationary guide so as to be movable in both directions; this essentially consists of guide rods 42 guided one below the other and parallel to one another and a guide frame 43 supporting them.

With regard to the mobility and adjustability of the casting body 1 with respect to the housing 25, the embodiment in question is formed in the same way as that of FIGS. 2 to 4.

The front container is detachably fastened to a vehicle 44, the wheel sets 45 of which are equipped with eccentric bushings (not shown) and are height-adjustable with respect to the vehicle frame 46 - indicated by the double arrow 46 '. The vehicle 44 can be moved along a guideway 48 in the direction of the double arrow 49 by means of a hydraulic cylinder 47, which is connected to the vehicle as well as to the surroundings in an articulated manner.

A steel pan 50 is held movably above the front container 2. This must cooperate with the front container 2 during the casting process in such a way that air access to the molten steel from the outside is excluded with certainty. This can be achieved in a manner known per se in that the steel pan 50 engages sufficiently deep into the front container via an immersion tube 51 with outlet openings 51 'and in that its molten pool level is covered to the outside by a layer of slag.

In the preheating position (Fig. 5) of the pouring body 1 on his carriage 24 and the header 2 on his vehicle 44 so far apart that left in the space between the double belt casting machine 10 and the pouring body 1 on the one hand and in the space between this and the Connection surface 9 'of the front container 2, on the other hand, a burner 52 or 53 can be swiveled in. By means of these burners, the pouring body 1 can be preheated from the side of its outlet cross section 19 'or the bottom channel 6 of the front container 2 from the connection surface 9' without difficulty.

At least one additional burner 54 is also assigned to the front container 2, via which the melting chamber 4 of the front container can also be preheated directly.

All of the burners 52 to 54 are held on pivot arms 52 ', 53' and 54 'so that they can be moved transversely to the plane of the drawing from a rest position to the illustrated position.

For reasons of clarity, the floor channel 6 is shown as a component of only the stone 9 with the connection surface 9 '.

The feed device for steel casting according to the invention is expediently handled as follows: starting from the preheating position shown in FIG. 5, the sufficiently preheated casting body 1 is turned by turning the eccentric 38 'into its inclined position, which enables it to be threaded between the lateral mold walls 20 "(ie the insulating block chains) brought and then move by moving its carriage 24 a few millimeters further than this corresponds to the casting position (shown in Fig. 6) in the direction of the double belt casting machine 10; the outlet cross section 19 'of the mouthpiece 19 thus projects deeper than in this intermediate position necessary for operation between the mold walls 20 and 20 ".

As soon as the pouring body 1 has reached the intermediate position, the front container 2, the stone 9 of which has been coated with a layer of a pasty sealing compound 22 in the region of the convex connecting surface 9 'serving as ball stud, is brought in the direction of the pouring body 1 into the intended pouring position and clamped there. Thereafter, the carriage 24 is sensitively set back against the front container so far that the connecting surfaces 9 'and 13 "are supported against one another by the layer of sealing compound 22 and thus form a ball joint sealed to the outside. Immediately after the connection between the casting body 1 and the front container has been formed 2, the casting process can be initiated by lifting the stopper rod 11 (cf. FIG. 1). The seal between the mouthpiece 19 of the casting body 1 and the mold walls 20 and 20 "surrounding it is ensured by maintaining a narrow sealing gap which is approximately 0. Is 3 mm. The advantage that is achieved by moving to an intermediate position of the casting body is that the attachment container 2, which has a considerable mass and is consequently difficult to handle, can be brought undisturbed into its pouring position before the lighter pouring body 1 is sensitive to the attachment container while avoiding damage is moved up.

The sensitive alignment of the casting body 1 with respect to the mold walls 20 and 20 "and the maintenance of a tight sealing gap which is as constant as possible is also particularly important when the molten steel is poured under pressure. The molten bath level inside the front container 2 is constantly at a level which lies above the outlet cross section 19 'in the double belt casting machine 10. The die casting process presupposes that the seal between the casting body and the mold walls withstands the increased metallostatic pressure in this area, since the casting body 1 in the casting position simultaneously via its pivot axis 23 and via the ball joint is held with the connecting surfaces 9 'and 13 ", but as the pouring time progresses, an extension of the suspended front container 2 (and thus a movement of the stone 9 downwards) is to be expected, it may be of considerable importance that the ceramic inner excl divide 13 can perform a compensatory movement within the steel jacket 16 against the resilient heat insulation layer 15.

The heat insulating layer 15 preferably consists of aluminum oxide fibers, aluminum silicate fibers and an organic binder (chemical composition: 72% A1 ₂ 0 ₃ , 21% Si0 ₂ , the rest of the binder). Above a temperature of about 400 ° C, the binder changes into the gaseous state, so that the heat insulation layer then only consists of the components A1 ₂ 0 ₃ and Si0 ₂ exists.

Claims (8)

1. Feed apparatus for introducing molten steel into continuous-casting machines with chill mould walls moved in the casting direction, having a sprue body (1) closed in tubular form and movable and vertically adjustable in relation to the continuous-casting machine (10), a mouthpiece (19) extending between the chill mould walls (20, 20"), by which a sealing gap can be produced with these walls and which is preceded by a front reservoir (2), the latter being adjustable in height and of the two parts connectable with one another by way of the sprue body - continuous-casting machine (10) and front reservoir (2) - at least the latter being mobile, characterised in that the sprue body (1) held rotatably about a horizontal pivot axis (23), forms with its own carriage (24) a sprue unit which, separately from the front reservoir (2) and from the continuous-casting machine in the configuration of a known double-belt casting machine (10) with chill mould walls (20, 20") moved exclusively in the casting direction (arrow 18), is mobile and is attachable to the front reservoir (2) through a ball joint of which the ball socket and ball pin, each of which forming a connection face (13" and 9' respectively), each pertain to different parts, namely either the front reservoir (2) or the sprue body (1), and in that the latter is laterally adjustable transversely of its longitudinal extent.

2. Apparatus according to Claim 1, characterised in that the movement clearance of the sprue unit (parts 1, 24) in relation to the double-belt casting machine (10) and that of the front reservoir (2) in relation to the sprue unit are at least so dimensioned that the sprue body (1) is pre-heatable from its mouthpiece (19) and the front reservoir (2) is pre-heatable from its attachment face (9'), by means of burners (52 and 53 respectively) movable in their regions.

3. Apparatus according to Claim 1 or 2, characterised in that the sprue body (1) is supported on its carriage (24) in see-saw manner by means of a weight balance (30).

4. Apparatus according to Claim 3, characterised in that the weight balance consists of a buffer (30) with variable spring characteristics.

5. Apparatus according to one of Claims 1 to 4, characterised in that the sprue body (1) is supportable outside its pivot axis (23) on a securable inclination eccentric (35) arranged on the carriage (24) and comprises on its underside a metallic centring part (41) with bevelled side faces (41') by means of which the sprue body can be threaded in between the lateral chill mould walls (20") - which project beyond the other chill mould walls (20) in a direction opposite to the casting direction (arrow 18).

6. Apparatus according to one of Claims 1 to 5, characterised in that the attachment faces (9' and 13") are supported on one another through a sealing mass (22) of plastic material.

7. Apparatus according to Claim 6, characterised in that the sealing mass (22), which in the temperature range between about 1,100 and 1,500 °C has a pasty condition, is composed of the essential components Si0₂, AI₂0₃, B₂0₃, CaO, Na₂0 and K₂0, in order according to the size of the proportions.

8. Apparatus according to one of Claims 1 to 7, having a sprue body (1) the ceramic inner fining (13) of which is supported through a thermally insulating layer (15) on an externally situated steel shell (16), characterised in that the thermally insulating layer (15) is formed as a spring element by means of which compensating movements can be executed between the ceramic inner lining (13) and the steel shell (16).

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