GB2198979A

GB2198979A - Rotary sliding gate valves for metallurgical vessels

Info

Publication number: GB2198979A
Application number: GB08729625A
Authority: GB
Inventors: Hans Rothfuss
Original assignee: Didier Werke AG
Current assignee: Didier Werke AG
Priority date: 1986-12-20
Filing date: 1987-12-18
Publication date: 1988-06-29
Also published as: JPH01143757A; GB8729625D0; SE8704895D0; SE8704895L

Abstract

A rotary sliding gate, valve for a metallurgical vessel comprises a refractory nozzle brick (4) and a refractory rotary body (15, 16) which sealingly engages it and is rotatable about an axis (17). The passage (8) through the nozzle brick (4) is offset from the axis (17). The rotary body includes a pouring or outlet tube (15) which defines a passage (20) whose axis is coincident with the axis (17) and a flange portion (16) which defines at least one connecting passage (19) of which one end is in communication with the passage (20) in the pouring tube and the other end may be selectively moved into registry with the passage (8) in the nozzle brick. The rotary member (15, 16) is carried by a rotary cage (21). The rotary cage and the rotary member have cooperating, radially extending tongues and grooves (23, 22) which transmit torque from the rotary cage to the rotary member. <IMAGE>

Description

ROTARY SLIDING GATE VALVES FOR METALLURGICAL VESSELS The invention relates to rotary sliding gate valves for metallurgical vessels, particularly for vessels for filling moulds with steel melt, and is concerned with that type of valve which comprises a fixed refractory nozzle brick which, in use, is arranged in the floor of the vessel and a refractory rotary body which sealingly engages it and is rotatable about an axis, the nozzle brick having a passage through it which is offset from the axis of rotation and the rotary body having a passage through it which selectively connects the nozzle brick passage to an outlet on the axis of rotation.

Such a rotary sliding gate valve is disclosed in Austrian Patent No.322753 and is in practice intended to transfer molten metal from an intermediate vessel into the mould of a continuous casting installation by diverting the molten metal from an eccentric supply to an outlet lying on the axis of rotation because when the slider is moved in the opening or closing direction the position of the pouring tube extending into the mould remains unchanged. An additional underplate used with conventional rotary sliding gate valves for connecting the outlet or the pouring tube, for instance in the form of an immersion nozzle, is not necessary.

However, the inadequate construction of the movable portion of the valve and the construction and the replaceable arrangement of the various refractory components in the associated metallic components are disadvantageous as regards handling and efficiency.

It is an object of the present invention to provide an improved construction of rotary sliding gate valve with an eccentric supply and central discharge of the molten metal which is associated with an increased performance.

According to the present invention there is provided a rotary sliding gate valve for a metallurgical vessel comprising a refractory nozzle brick and a refractory rotary body which sealingly engages it and is rotatable about an axis, the passage through the nozzle brick being offset from the said axis, the rotary body including a pouring or outlet tube which defines a passage whose axis is coincident with the said axis and a flange portion which defines at least one connecting passage of which one end is in communication with the passage in the pouring tube and the other end may be selectively moved into registry with the passage in the nozzle brick, the rotary body being carried by a rotary cage, the rotary cage and the rotary body having cooperating recess and projection means by which torque may be transmitted from the former to the latter.Such a construction of the valve permits the placing of the connecting passage between the eccentric passage in the nozzle brick and the central axial bore in the rotary body with comparatively little manufacturing complexity while substantially taking thermal requirements into account so that a substantially uniform, stress-free thermal action of the melt on the rotary body is achieved during operation which extends its service life.

Furthermore, the form-sealing connection of the rotary body with the rotary cage carrying it by way of cooperating recesses and projections is both simple and transmits the necessary torque in an operationally reliable manner whereby the necessary manual operations are maintained at a minimum.

It has been found to be particularly convenient if the outer surface of the flange portion of the rotary body comprises a frusto-conical portion which engages a complementary surface on the rotary cage, the two complementary surfaces affording the cooperating recess and projection means. The use of tongues and grooves is particularly preferred since this construction is problem-free and enables the replacement of the rotary body on the rotary cage by simply removing the old one and inserting a new one.

It is also advantageous as regards the flow characteristics if the or each connecting passage is of spiral shape. It is also advantageous to provide a plurality, preferably three, of equally spaced connecting passages in the flange portion. In this construction the rotary body is provided with a plurality of reserve passages which can be used selectively one after the other, if desired. It is also possible to provide a plurality of discharge passages in the nozzle brick, all which may be simultaneously in registry with a respective connecting passage. The flow of the melt is thus divided and thus the control of the valve or the setting of a desired flow rate of the melt is more precise. Additionally, the thermal loading of the rotary body is rendered eyen more uniform.

If the nozzle brick is appropriately manufactured of high grade refractory material it can directly afford the stationary sliding surface which engages the sliding surface of the rotary body. It has, however, proved to be particularly economically favourable if the nozzle brick includes a wear member which is replaceably mounted therein and secured against rotation and which affords the sliding surface which cooperates with the sliding surface on the rotary body.

It is also possible in certain cases for the wear member to define the full length of the discharge passages in the nozzle brick.

In one embodiment of the invention the cooperating sliding surfaces of the nozzle brick and the rotary body together define an annular groove which communicates with an external fluid connection via a passage in the nozzle brick and with the axial passage in the pouring tube via one or more passages in the flange portion. This arrangement conveniently permits, for instance, the introduction of oxygen for burning up melt solidified in the discharge passages above the rotary body. Inert gas can also be introduced, for instance to prevent solidification or for metallurgical treatment of the melt.

The pouring or outlet tube may be relatively long and thus, in use, dip into the melt in the mould in order to shield the poured stream from atmospheric air.

Alternatively, it may be preferable from the point of view of manufacture and manual handling if the valve includes a housing out of which the rotary cage extends, the portion of the rotary cage outside the housing including connecting means for carrying a tube extension forming a continuation of the pouring tube.

The invention also embraces a valve of the type referred to above in situ on a metallurgical vessel with the nozzle brick disposed in the floor of the vessel. A reacticn force to the sealing force applied by the rotary body to the nozzle brick is produced in a constructionally simple manner if the floor of the vessel includes a refractory lining below which is a base plate, the nozzle brick being anchored to the base plate by means of clamps and being mounted in the refractory lining in a layer of refractory concrete.

When used in a continuous casting installation the pouring tube may constitute an immersion nozzle extending into the mould.

The invention also embraces a rotary body for such a valve.

For ease of replacement of the wear parts of the rotary sliding gate valve, in particular the rotary body, a stopper valve of known type can be arranged in the vessel by which the inlet to the valve can be closed if desired.

Further features and details of the invention will be apparent from the following description of certain exemplary embodiment which is given with reference to the accompanying drawings, in which: Figure 1 is a vertical sectional view of a rotary sliding gate valve in accordance with the invention; Figure 2 is a plan view of the rotary body of the valve of Figure 1; Figure 3 is a plan view of the wear member 9 of the valve of Figure 1; and Figures 4 to 6 are simplified scrap views of further embodiments.

Figure 1 shows the outlet region of a metallurgical vessel with a metallic bottom plate 2 and a refractory bottom lining 3 in which a nozzle brick 4 is mounted by means of pivotable hooks 5. The nozzle brick 4 is surrounded by a refractory concrete layer 6 which can be broken away and replaced from the interior of the vessel. The nozzle brick 4 has three equiangularly spaced discharge passages 8 provided with respective wear liners or sleeves 7. Set in a recess 13 in the lower surface of the nozzle brick 4 is a wear plate 9 which supports the discharge sleeves 7 and has holes 10 constituting continuations of the discharge passages 8 and at least one sliding surface 11. As seen in Figure 3, the wear plate 9 is of overall circular shape but has three straight sections 12 on its periphery by which it is replaceably retained in the complementarily shaped recess 13.In addition to those functions which are conventional in sliding gate valves the nozzle brick 4 thus supports the wear plate 9 whose sliding surface 11 cooperates with the sliding surface 14 of a rotary valve body 15,16 comprising a depending refractory tube 15 at the top of which is a flange or widened thickened portion 16 of circular shape. The rotary axis 17 of the rotary body is coincident with the axis of the tube 15 and with the centre of a construction circle 18 on which the discharge passages 8 and the wear plate holes 10 lie equiangularly distributed, when viewed in the axial direction, as in Figures 2 and 3. The circle 18 has a radius about half that of the sliding surface 14 of the rotary body.Connecting bores 19 extend from the sliding surface 14 at positions corresponding to those of the passages 8 and 10 to the passage 20 within the tube 15 of the rotary body 15,16 so that when the connecting bores 19 are rotated beneath the discharge passages 8 melt flows from the vessel 1 to the axial bore 20 but when the bores 19 are in an intermediate position no flow occurs.

For the purpose of rotation, the rotary body 15,16 is mounted in a rotary cage 21 and torque is transmitted between them via a form sealing or interlocking connection 22,23 which comprises radial grooves 22 in the conical peripheral-surface 25 of the flange 16 and complementarily shaped tongues 23 on the rotary cage 21. Alternatively meshing teeth can be used for the torque transmission or the grooves 22 may, as shown in Figure 4, be deepened and the tongues 23 correspondingly enlarged. In this latter manner the connection 22,23 has a deeper engagement which permits fewer peripherally distributed tongue and groove pairs to be used.

Beneath the connection 22,23 the rotary cage 21 has an annular gear 26 on which a drive pinion 27 acts which is drivingly coupled to a drive unit (not shown) and is positioned in a bulge or protruding portion 28 of the valve housing 29 which encloses the annular gear 26. The housing 29 carries an annular disc shaped housing lid 31 which is mounted on housing screws or pins 30 and which supports the rotary cage 21 by means of a divisible ball bearing 32. Plate springs 33 provided on the screws 30 press the sliding surface 14 of the rotary body 15,16 against the sliding surface 11 of the wear plate 9 in a resilient but sealed manner.

After releasing the screws 30 mounted on the peripheral side of the housing 29, the housing 31 can be pivoted about a hinge, which is not illustrated in the drawing, present at a peripheral position between the housing 29 and the lid 31 so that the rotary body 15,16 and the rotary cage 21, which both project outwardly through the central opening of the lid 31, are accessible. A refractory extension tube 35 with a slightly conical external surface 36 is connected to the rotary body 15,16 by a threaded sleeve 37 which is firmly screwed to the rotary cage 21.

The symmetrical arrangement illustrated in Figure 1 of the discharge passages 8, the holes 10 and the connecting bores 19 results in a uniform, substantially stress-free thermal loading of the nozzle brick 4, wear plate 9 and rotary body 15,16 by the melt flowing through them which benefits the service life of these components.

Figure 5 illustrates an alternative embodiment which has only one passage 8,19, that is to say the nozzle brick 4 has one discharge passage 8 and the rotary body 15,16 one connecting bore 19 to the axial bore 20. Furthermore, the nozzle brick 4 does not have a separate wear sleeve in the discharge passage 8 and is thus manufactured from high grade refractory material which allows the fixed sliding surface 11 to be arranged directly on the nozzle brick 4.

Additionally, in distinction to the embodiment of Figures 1 to 3, the sliding surface 11 is concave and the opposing sliding surface 14 on the rotary body 15,16 is shaped correspondingly convexly which assists in evening out any variation in the contact pressure of the rotary body 15,16.

In Figure 6, the sleeveless discharge passage 8 and the fixed sliding surface 11 are provided by a highly wear resistant frusto-conical brick 38 which is replaceably disposed in the nozzle brick 4. Extending through both bricks 4 and 38 is a gas passage 39 which has an external gas connection 40 and communicates with an annular groove 41 mutually defined by the sliding surfaces 11 and 14. One or more nozzles or passages 42 in the flange 16 connects the groove 41 with the axial bore 20 in the rotary body 15,16. The peripheral groove 41 and the axial bore 20 can be supplied with gas via the gas connection 40 whereby the gas pressure in the groove 41 prevents the ingress of air between the sliding surfaces 11 and 14 into the flow of molten metal whilst the introduction of gas into the axial bore 20 can serve to prevent solidification or to purge the molten metal.

Claims

1. A rotary sliding gate valve for a metallurgical vessel comprising a refractory nozzle brick and a refractory rotary body which sealingly engages it and is rotatable about an axis, the passage through the nozzle brick being offset from the said axis, the rotary body including a pouring or outlet tube which defines a passage whose axis is coincident with the said axis and a flange portion which defines at least one connecting passage of which one end is in communication with the passage in the pouring tube and the other end may be selectively moved into registry with the passage in the nozzle brick, the rotary body being carried by a rotary cage, the rotary cage and the rotary body having cooperating recess and projection means by which torque may be transmitted from the former to the latter.

2. A valve as claimed in claim 1 in which the outer surface of the flange portion of the rotary body comprises a frusto-conical portion which engages a complementary surface on the rotary cage, the two complementary surfaces affording the cooperating recess and projection means.

3. A valve as claimed in claim 2 in which the recess and projection means comprise radially extending tongues and grooves.

4. A valve as claimed in any one of claims 1 to 3 in which the or each connecting passage is of spiral shape.

5. A valve as claimed in any one of the preceding claims including a plurality of equally spaced connecting passages in the flange portion.

6. A valve as claimed in claim 5 including a plurality of discharge passages in the nozzle brick, all which may be simultaneously in registry with a respective connecting passage.

7. A valve as claimed in any one of the preceding claims in which the nozzle brick includes a wear member which is replaceably mounted therein and secured against rotation and which affords the sliding surface which cooperates with the sliding surface on the rotary body.

8. A valve as claimed in claim 7 in which the wear member defines the full length of the discharge passages in the nozzle brick.

9. A valve as claimed in any one of the preceding claims in which the cooperating sliding surfaces of the nozzle brick and the rotary body together define an annular groove which communicates with an external fluid connection via a passage in the nozzle brick and with the axial passage in the pouring tube via one or more passages in the flange portion.

10. A valve as claimed in any one of the preceding claims including a housing out of which the rotary cage extends, the portion of the rotary cage outside the housing including connecting means for carrying a tube extension forming a continuation of the pouring tube.

11. A valve as claimed in any one of the preceding claims in situ on a metallurgical vessel with the nozzle brick disposed in the floor of the vessel.

12. A valve as claimed in claim 11 in which the floor of the vessel includes a refractory lining below which is a base plate, the nozzle brick being anchored to the base plate by means of clamps and being mounted in the refractory lining in a layer of refractory concrete.

13. A valve as claimed in claim 11 or 12 in use in a continuous casting installation, the pouring tube constituting an immersion nozzle extending into the mould.

14. A refractory rotary body for a rotary sliding gate valve as claimed in any one of the preceding claims comprising a pouring tube which defines a passage and a flange portion at one end of the pouring tube which defines at least one connecting passage which communicates with the passage in the pouring tube and extends at an angle thereto and opens through the sliding surface on the flange portion, the flange portion having torque-transmitting means comprising recess means or projection means for engagement with projection means or recess means, respectively, on the rotary cage.

15. A rotary body as claimed in claim 14 in which the outer surface of the flange portion comprises a frustoconical portion which affords the torque-transmission means.

16. A rotary body as claimed in claim 15 in which the torque-transmission means comprise radially extending grooves.

17. A rotary body as claimed in any one of claims 14 to 16 in which the or each connecting passage is of spiral shape.

18. A rotary body as claimed in any one of claims 14 to 17 including a plurality of equiangularly spaced connecting passages.

19. A rotary body as claimed in any one of claims 14 to 18 in which the sliding surface is convex.

20. A rotary body as claimed in any one of claims 14 to 19 in which an annular groove is provided in the sliding surface which communicates via at least one passage in the flange portion with the passage in the pouring tube.

21. A rotary sliding gate valve for a metallurgical vessel substantially as specifically herein described with reference to Figures 1 to 3, optionally as modified by any one of Figures 4 to 6 of the accompanying drawings.