EP2543455B1 - Fire-resistant ceramic sliding plate and accompanying sliding plate set - Google Patents

Description

The invention relates to a slide plate set of a refractory ceramic slide plate and at least one further plate for aligned contact with corresponding main surfaces in their functional position.

A single slide plate or the associated slide plate set are components of a slide valve closure (slide system) for controlling the outflow and outflow rate of a molten metal from a metallurgical vessel, such as a ladle or an intermediate container (English: tundish).

Slide systems of the type mentioned include so-called linear slide and rotary valve. They can include two or more plates. In this case, at least one of the plates is movable (in the case of a linear slide: linearly movable, in the case of a rotary slide valve: rotationally movable). Each plate has two parallel main surfaces and at least one opening extending between the main surfaces, that is perpendicular to the main surfaces.

By displacing the movable plate (hereafter referred to as slide plate), corresponding openings of the plates can be offset, partially overlapping or aligned with each other to adjust the mass and velocity of the melt passed therethrough or to interrupt the melt flow.

All panels are made of a refractory ceramic material capable of withstanding the high temperatures of the molten metal (for example 1500 ° C). In particular, when opening and closing the slide closure, there are strong corrosion phenomena of the refractory material.

The EP 0 373 287 A2 describes a slide plate having a plurality of flow openings, so that the slide plate can be used even if the first flow opening is worn by the second flow opening is used to control the slide closure.

Alternatively sees the DE 103 24 801 A1 to form the flow openings of the slide plate with different diameters, so that depending on the use of one or the other flow opening more or less molten metal can flow through the control valve (the gate valve).

The invention has for its object to offer a slide plate set that allows optimized flow of the passed molten metal.

• zwei parallel zueinander verlaufenden Haupt-Oberflächen,
• mindestens zwei, im Abstand voneinander angeordneten Ausgussöffnungen, die sich jeweils zwischen den Haupt-Oberflächen erstrecken, wobei
• im Bereich mindestens einer Haupt-Oberfläche mindestens zwei Ausgussöffnungen unterschiedliche Querschnittsflächen aufweisen

liegt der Erfindungsgedanke darin, die Schieberplatte so auszubilden, dass

• der kürzeste Abstand von zwei benachbarten Ausgussöffnungen, entlang der Haupt-Oberfläche, kleiner ist als die größte Sehne der beiden Ausgussöffnungen.

Starting from the above-mentioned, known slide plate with the following features:

• two parallel main surfaces,
• at least two spaced spout openings each extending between the main surfaces, wherein
• at least two spout openings have different cross-sectional areas in the region of at least one main surface

lies the inventive idea is to form the slide plate so that

• the shortest distance from two adjacent spouts, along the main surface, is smaller than the largest chord of the two spouts.

The shortest distance between two circular openings is the distance along a straight line passing through the centers of the openings. Often, this straight line will define the direction of displacement of the slide plate in a linear slide.

The term "displacement direction of the slide plate" is basically a straight line in a linear slide, with a rotary slide the direction of displacement runs along a circular arc.

1. a) Eine Ausflussöffnung der Schieberplatte wird fluchtend mit einer Ausgussöffnung der weiteren Platte ausgerichtet. Das bedeutet, dass die Ausflussöffnungen beider Platten jeweils eine identische Querschnittsfläche aufweisen. Die Durchflussmenge ist maximal.
2. b) Verschiebt man die Schieberplatte gemäß Beispiel a), so verringert sich die gemeinsame Querschnittsfläche der Ausflussöffnungen beider Platten und entsprechend die Durchflussmenge.
3. c) Verschiebt man die Schieberplatte weiter, bis eine zweite Ausflussöffnung der Schieberplatte in strömungstechnische Verbindung mit der Ausflussöffnung der weiteren Platte gebracht ist, ergibt sich solange ein Durchflussprofil mit zwei Teilströmungen, bis eine Öffnung der Schieberplatte keine Überschneidung mehr mit der Öffnung der weiteren Platte hat.

Due to the inventive dimensioning (assignment) of adjacent spout openings of the slide plate a variety of settings of the slide closure are possible in total. This will be explained below with reference to a 2-plate gate valve closure. It goes without saying that the features described therein also apply analogously to slider closures with more than two plates.

1. a) An outflow opening of the slide plate is aligned with a spout opening of the other plate. This means that the outflow openings of both plates each have an identical cross-sectional area. The flow rate is maximum.
2. b) Shifts the slide plate according to Example a), so reduces the common cross-sectional area of the outflow openings of both plates and according to the flow rate.
3. c) Moves the slide plate further until a second outflow opening of the slide plate is brought into fluid communication with the outflow of the other plate, as long as a flow profile with two partial flows, until an opening of the slide plate has no overlap with the opening of the other plate ,

While the measures according to a) and b) can also be carried out in the case of slide gate closures according to the prior art mentioned at the outset, the essential advantage of the solution according to the invention exists in that (c) that at least two flow openings of the slide plate designed according to the invention can also be brought into fluidic connection with a discharge opening of a further plate of the slide closure at the same time. In this case, the melt stream is divided into at least two partial streams. A first partial flow flows through the spout opening of the further plate of the spool closure and then through a portion of the first spout opening, while a second partial flow also flows through the spout opening of the further (usually stationary) plate of the spool closure and then through at least a portion of the second spout opening of the spool plate ,

By this division, the flow rate of the partial streams as well as the total mass of the melt passed through can be set (controlled, controlled) within wide limits. This results in a characteristically different flow pattern. Reference is made to the following description of the figures.

The essential feature of the slide plate is thus to allow optimized control with less wear via at least one second pouring hole (a second pouring opening), which can be switched fluidically at least partially parallel to the first pouring hole.

With a strong throttling (reduction of the melt stream), the vast majority of the pouring stream can be poured off via a small pouring spout, which is brought completely under the spout opening of the associated (further) plate of the spool closure. The larger spout opening can serve together with the other opening for fine control of the flow rate of the molten metal, depending after, to what extent it is additionally brought into fluid communication with the spout opening of the further plate (s).

A reduced amount of melt that flows through a restricted spout opening in the constellation described above causes only less erosion / corrosion.

In addition, the risk is reduced that air is sucked in the region of the slide closure, provided that the casting takes place largely on the smaller spout opening and only sections of the larger spout opening are also in fluid communication with the spout opening of the associated plate. This is due to the fact that the melt flow through the smaller spout opening then takes place centrally (for example coaxially) with respect to the spout openings of the further plates. In other words, in this position, the spout opening of the slide plate always has a clearance from the boundary wall of the spout opening of the associated (usually solid) plate. This too is evident from the following description of the figures.

The aforementioned principle applies analogously to slide plates with more than 2 outflow openings, for example with 3 or 4 openings.

In one embodiment, the shortest distance from two adjacent spout openings (along the respective main surface) is 0.01 to 0.5 times the largest chord of the two spout openings.

This distance may, in one embodiment, be limited to a lower limit of 0.05 and / or an upper limit of 0.35.

An alternative lower limit is 0.1, another possible upper limit is 0.25 or 0.30.

An embodiment of the invention provides that in the region of at least one main surface, the sum of the cross-sectional area of the small-cross-sectional area spout and x times the cross-sectional area of the large cross-sectional area spout is greater than or equal to the cross-sectional area of the large cross-section spout x has a value ≥ 0.4 and ≤ 0.95, in particular a value ≤ 0.9, ≤ 0.8 or ≤ 0.7 or ≤ 0.6 with lower limit values ≥ 0.45, ≥ 0.50 or ≥ 0.55.

The above calculation can be represented as a formula as follows: $$\mathrm{QS}20\ge \mathrm{QS}10\left(1-\mathrm{x}\right)\mathrm{,}$$

QS20 is the cross-sectional area of the small cross-sectional area spout and QS10 is the cross-sectional area of the large cross-sectional area spout.

In the case of two circular openings, suitable lower limits for x are 0.10; 0.20 or 0.25 and appropriate upper limits for x at 0.90; 0.80 or 0.70, where QS defines the respective circle diameter.

wobei Σ QS20 die Querschnitte der Ausgussöffnungen erfasst, die gleichzeitig mit der Ausgussöffnung mit großem Querschnitt (QS10) in strömungstechnische Verbindung mit einer Ausgussöffnung einer benachbarten Platte gebracht werden können, wobei Σ QS20 nicht QS10 enthält.In the case of more than two spouts: $$\mathrm{\Sigma QS}20\ge \mathrm{QS}10\left(1-\mathrm{x}\right)$$

wherein Σ QS20 detects the cross-sections of the spout openings that can be brought into fluid communication with a spout opening of an adjacent plate simultaneously with the spout with large cross-section (QS10), wherein Σ QS20 does not contain QS10.

It is not absolutely necessary that the spout opening (s) have a circular cross section, although this is preferred. In principle, the spout openings can have any geometric cross-section, for example rectangular or polygonal.

Typically, the cross-sectional area of the spout openings between the main surfaces is constant, so that results in a circular cross-section, a cylindrical spout opening. However, the invention is not limited to such embodiments, it also includes spout openings, which for example have a funnel-shaped profile.

The centers of the spout openings along a main surface may lie on a common straight line in the case of a linear spool closure and on a common circular line in the case of a rotary spool closure. This information is not in the exact mathematical sense, but to understand technical, for example, taking into account production tolerances. You can also be arranged offset to the direction of displacement, as shown in the following embodiment.

The complete slide plate set (a complete slide closure), consists of at least one slide plate of the aforementioned type and at least one further plate, wherein corresponding plates are aligned in their functional position with their respective main surfaces flat against each other. In this case, the at least one further plate has at least one spout opening, the cross-sectional area and arrangement of which are selected such that it completely and / or partially covers one or more spout openings of the slide plate as a function of the position of the slide plate.

It goes without saying that the slide plate, like the further plate (s), can be designed according to the state of the art with respect to its respective material or its assembly (for example in a metal cassette).

1. a) nur die Ausgussöffnung der Schieberplatte mit kleiner Querschnittsfläche oder
2. b) die Ausgussöffnung der Schieberplatte mit kleiner Querschnittsfläche und gleichzeitig bis zu 50 % der Ausgussöffnung der Schieberplatte mit großer Querschnittsfläche überdeckt, oder
3. c) nur die Ausgussöffnung der Schieberplatte mit großer Querschnittsfläche abdeckt.

The further plate has, according to one embodiment, at least one spout opening whose cross-sectional area and arrangement are selected such that they depend on the position of the slide plate

1. a) only the spout opening of the slide plate with a small cross-sectional area or
2. b) the spout opening of the slide plate with a small cross-sectional area and simultaneously covers up to 50% of the spout opening of the slide plate with a large cross-sectional area, or
3. c) covers only the spout opening of the slide plate with a large cross-sectional area.

The value 50% can be extended to 60%, but smaller values (≤45%, ≤ 40%, ≤ 30%) are preferred, so that as much melt as possible flows through the smaller opening.

The centers of all spouts are preferably along corresponding major surfaces in a common plane that is perpendicular to the major surfaces. This applies to a linear slide gate valve.

In a rotary valve closure, the centers of all spouts are along corresponding major surfaces in a common cylinder surface surface that is perpendicular to the main surfaces.

Figur 1:

Eine Aufsicht und ein Querschnitt durch eine Schieberplatte gemäß der Erfindung.

Figur 2:

Einen Querschnitt durch ein erfindungsgemäßes Schieberplattenset.

Figur 3:

Eine beispielhafte Position des Schieberplattensets gemäß Figur 2.

Figur 4:

Eine Darstellung analog Figur 3 für ein Schieberplattenset gemäß Stand der Technik.

Figur 5:

Ein weiteres Ausführungsbeispiel für eine Schieberplatte in Zuordnung zu einer weiteren Platte.

Figur 6:

Ein weiteres Ausführungsbeispiel für eine Schieberplatte in Zuordnung zu einer weiteren Platte.

Figur 7:

Ein weiteres Ausführungsbeispiel für eine Schieberplatte in Zuordnung zu einer weiteren Platte.

Figur 8:

Ein weiteres Ausführungsbeispiel für einen Drehschieberverschluss in Zuordnung zu einer weiteren Platte.

The invention will be explained in more detail below with reference to various embodiments and in comparison with the prior art. This shows, in each case in a highly schematic representation:

FIG. 1:

A plan view and a cross section through a slide plate according to the invention.

FIG. 2:

A cross section through an inventive Schieberplattenset.

FIG. 3:

An exemplary position of the slide plate set according to FIG. 2 ,

FIG. 4:

A representation analog FIG. 3 for a slider plate set according to the prior art.

FIG. 5:

Another embodiment of a slide plate in association with another plate.

FIG. 6:

Another embodiment of a slide plate in association with another plate.

FIG. 7:

Another embodiment of a slide plate in association with another plate.

FIG. 8:

Another embodiment of a rotary valve closure in association with another plate.

In the figures, the same or equivalent components are shown with the same reference numerals.

FIG. 1 shows a slide plate S having an upper main surface SO and a parallel lower main surface SU and in the top view (top in FIG. 1 ) has approximately an oval shape.

It is a slide plate for a linear slide valve closure, with the direction of displacement marked VV. Along the displacement direction VV are two spout openings S10, S20, each extending between the main surfaces SO, SU, at a distance s1 (where s1 is the shortest distance of the spout openings S10, S20 along the direction of displacement VV).

The larger spout opening S10 has a diameter SS10. The diameter of the smaller spout opening S20 is designated SS20.

Both spout openings S10, S20 have a constant circular cross-section between the main surfaces SO, SU, wherein the associated central longitudinal axes are denoted by MS 10, MS20.

FIG. 2 shows the assignment of such a slide plate S in a 3-plate slide valve closure. It follows that the corresponding slide plate set comprises three plates, namely an upper, fixed plate PO and a lower, fixed plate PU. Between two or the bottom POU of the plate PO and the top PUO of the plate PU extends the slide plate S. The plates PO, PU each have a pouring opening PO10, PU10, each with a circular cross-section and the same dimensions to the spout opening S 10 of the slide plate S.

In the illustrated position all spouts are PO10. S10, PU10 aligned with each other.

The smaller spout opening S20 of the slide plate S is covered upwardly by the plate PO and bounded below by the plate PU. In other words: in the position shown, no molten metal flows out of the above-arranged melting vessel SG or the associated sleeve H into downstream aggregates through the spout opening S20, which are denoted here only schematically by A.

Further details of the slider closure, such as the cartridge holder for the plates, the sliding mechanism for the slide plate, etc. are not explained in detail, because they are state of the art.

FIG. 3 shows a position of the slide plate S, compared to the position according to FIG. 2 is shifted to the left, so that the smaller spout opening S20 is completely in the region of the spout opening PO10, but the larger spout opening S10 is still not completely removed from the covering area with the spouts PO10, PU10. This has the consequence that the melt stream, indicated schematically by M, is divided into two partial streams as soon as the melt has reached the region of the slide plate S. These partial flows are indicated by M10, M20 and simultaneously hatched corresponding flow profiles.

While the melt in the region of the spout opening PO10 has a speed G0, which it only reaches again when the melt has left the lower plate PU, the partial flow M10 has approximately a speed G2 which is greater than G0. In the region of the smaller spout opening S20, the flow profile is such that a region is formed in the center, in which the flow velocity G1 is greater than G2, wherein G2 is observed in the outer region of the melt stream M20. It goes without saying that the transitions between the individual speed data are not gradual, but continuous.

The representation according to FIG. 3 shows that due to the central position of the spout opening S20 below the spout opening PU10 a suction of external air is virtually excluded. At most in the transition region of the melt stream M10 between adjacent plates still a residual amount of external air can be sucked.

The inventive assignment of the two spout openings of the slide plate S thus not only increases the controllability of Schieberplattensets (the slide closure), but also improves the quality of the passed metal melt in comparison with the prior art due to lower oxidation.

The state of the art is in FIG. 4 shown. All spout openings of all plates are identical. In a linear displacement of the slide plate S, although it comes to a throttling (reducing the flow rate) of the molten metal. In this way, however, at the same time the risk of undesired air infiltration in the transition region between adjacent plates is increased. In addition, it has been observed that in the region of the edge K of the slide plate S, a deflection of the flow and a greatly increased flow velocity of the molten metal are formed, causing high corrosion and erosion. This can be avoided with the design according to the invention.

FIG. 5 shows another embodiment of a linear slide plate S. The diameter SS10 of the large flow passage S10 is 60 mm, the diameter SS20 of the small flow passage S20 is 25 mm, the shortest distance s1 between both spouts S10, S20 is 15 mm. The result for the spout opening S10 is a cross-sectional area of 2,827 mm ² , for S20 a value of 491 mm ² . The opening PO10 of an adjacent plate is indicated.

The value x for the above-mentioned formula is accordingly about 0.83. The direction of displacement is indicated by VV. The opening S20 is offset to the displacement direction VV (distance AB to the center of the opening S20).

In FIG. 6 is a linear slide plate S with the following values: SS 10 = 60 mm, SS20 = 25 mm. The diameter of the spout opening PO10 is also 60 mm. The distance S1 is 17 mm.

The spout opening S20 of the slide plate S is correspondingly completely and the spout opening S10 of the slide plate S to about 21.9% of the spout opening PU10 covered in the position shown.

In FIG. 7 is an embodiment similar FIG. 6 shown, wherein the spout openings, however, have no circular cross-section, but each having a square cross-section. It is readily apparent that in the illustrated allocation of the spouts PO10 of upper plate PO and slide plate S, the degree of coverage with the smaller spout opening S20 is 100% and the degree of coverage with the larger spout opening S10 is 50%.

FIG. 8 Finally, a representation is similar FIG. 5 However, for a rotary valve closure, wherein the circular displacement path is shown with VV.

With a cross-sectional area of 908 mm ² for the spout opening S20 and 7,854 mm ² for the spout opening S10 (the distance S1 is 30 mm) results in a value x of about 0.88.

The slide plate S may consist of a carbon-bonded material.

Claims (14)

1. Sliding plate set comprising a sliding plate (S) and at least one further plate (PO, PU) for an aligned arrangement with corresponding main surfaces in its functioning position, where the sliding plate features the following characteristics:

   1.1 Two main surfaces (SO, SU), running parallel to each other,

   1.2 At least two discharge openings (S 10, S20), arranged at a distance to each other, each of which extends between the main surfaces (SO, SU),

   1.3 In the area of at least one main surface (SO, SU), at least two discharge openings (S10, S20) feature different cross sectional areas (QS10, QS20),

   1.4 The shortest distance (s1) between two neighbouring discharge openings (S10, S20) along this main surface (SO, SU) is shorter than the largest axis (SS10) of both discharge openings (S10, S20) and the further plate (PO, PU) features at least one discharge opening (PO10, PU10), whose cross sectional area and arrangement are chosen in such a way that it covers one or more discharge openings (S10, S20) of the sliding plate (S) fully and/or partially, depending on the position of the sliding plate (S).
2. Sliding plate set according to Claim 1, wherein the further plate (PO, PU) features at least one discharge opening (PO10, PU10), whose cross sectional area und arrangement are chosen in such a way, that depending on the position of the sliding plate (S), it

   a) Only covers the discharge opening (S20) of the sliding plate (S) with a small cross sectional area or

   b) Covers the discharge opening (S20) of the sliding plate (S) with a small cross sectional area (QS20) and at the same time up to 50% of the discharge opening (S10) of the sliding plate with a larger cross sectional area (QS10).
3. Sliding plate set according to claim 1, wherein the centres (MS10, MS20, MK10) of all discharge openings (S10, S20, PO10, PU10) along corresponding main surfaces (POU, SO; SU, PUO) lie on a common level, which runs perpendicular to the main surfaces (SU, SO).
4. Sliding plate set according to claim 1, wherein the centres (MS10, MS20, MK10) of all discharge openings (S10, S20, PO10, PU10) along corresponding main surfaces (POU, SO; SU, PUO) lie in a common cylinder coat surface, which runs perpendicular to the main surfaces (SU, SO).
5. Sliding plate set according to claim 1 with a sliding plate (S), wherein the shortest distance (s1) of two neighbouring discharge openings (S10, S20) along this main surface (SO, SU) is 0.01 to 0.5 times the largest axis (SS10) of both discharge openings (S10, S20).
6. Sliding plate set according to claim 5 with a sliding plate (S), wherein the shortest distance (s1) of two neighbouring discharge openings (S10, S20) along this main surface (SO, SU) is 0.05 to 0.35 times the largest axis (SS10) of both discharge openings (S10, S20).
7. Sliding plate set according to claim 5 with a sliding plate (S), wherein the shortest distance (s1) of two neighbouring discharge openings (S10, S20) along this main surface (SO, SU) is 0.1 to 0.25 times the largest axis (SS10) of both discharge openings (S10, S20).
8. Sliding plate set according to claim 1 with a sliding plate (S), wherein in the area of at least one main surface (SO, SU) the sum of the cross-sectional area (QS20) of the discharge opening (S20) with a small cross sectional area and the cross sectional area (QS10) of the discharge opening (S10) with a large cross sectional area times x is larger than the total cross sectional area (QS10) of the discharge opening (S10) with a large cross section, wherein x being ≥ 0.4 and 0.9.
9. Sliding plate set according to claim 1 with a sliding plate (S), whose discharge openings (S10, S20) each feature a circular cross section in the area of the main surfaces (SO, SU).
10. Sliding plate set according to claim 1 with a sliding plate (S), whose discharge openings (S10, S20) each feature a constant cross sectional area between the main surfaces (SO, SU).
11. Sliding plate set according to claim 1 with a sliding plate (5), wherein the centres (MS10, MS20) of the discharge openings (S10, S20) along a main surface (SO, SU) lie on a common straight line.
12. Sliding plate set according to claim 11 with a sliding plate (S), wherein the common straight line defines the direction of displacement of the sliding plate.
13. Sliding plate according to claim 1 with a sliding plate (S), wherein the centres (MS10, MS20) of the discharge openings (S10, S20) along a main surface (SO, SU) lie on a common arc.
14. Sliding plate set according to claim 13 with a sliding plate (S), wherein the common arc defines the direction of displacement of the sliding plate.

Images