SLIDING GATE VALVES AND METHODS OF OPERATING THEM

Abstract: In a sliding gate valve assembly employed on the side of a furnace as a furnace valve, the stationary plate (20) has a well nozzle (19) secured thereto, in alignment with the flow orifice of the plate and projecting to the upstream side of the plate.

Description: This invention relates to sliding gate valves for controlling the flow of molten metal from the pour opening of a vessel, and to a refractory plate assembly for use as the stationary plate in such a valve. The invention is particularly concerned with sliding gate valve assemblies including a housing mounted in use on said vessel, a stationary refractory plate in said housing having a flow passage in open communication with said vessel pour opening, an orificed refractory slide gate movably mounted in said housing in pressure-sealed, face-to-face relation with said stationary plate and means for moving said slide gate with respect to said stationary plate to place the orifice therein into and out of registry with the stationary plate flow passage, the said stationary plate structure including a body of refractory material having a flow orifice and having a metal casing. The refractory material in such valve assemblies is subject to substantial erosion in use, and the plate structures require frequent replacement. The stationary plates can be of substantial size and weight and their replacement is a cumbersome process, performed with the assistance of a crane or hoist. Bringing together into correctly aligned engagement the sealing formations on the stationary plate and a well nozzle fitted in the vessel wall is difficult to achieve, bearing in mind that these formations are obscured from view. In US-A-4273315 there is shown a metal processing furnace equipped with a sliding gate valve assembly of the general construction described above. The stationary plate structure of this valve has a body of refractory material with an integral portion which projects in the upstream direction through the base of the metal casing and includes at its end an annular sealing rim. Upon installation of the stationary plate it is necessary to bring this sealing rim of the refractory into correctly aligned engagement with a complementary projection formed on the outermost brick defining the tapping channel of the furnace, and which must be fitted into the recess defined within the sealing rim. The invention has for its aim to make easier the installation of the stationary plate structure of a sliding gate valve assembly on a vessel. In accordance the invention provides a refractory plate assembly adapted for use as the stationary plate of a sliding gate valve for controlling the discharge of molten metal from a metal furnace or like vessel, the said assembly comprising a metallic casing housing a body of refractory material, the casing and the said body having aligned flow apertures therethrough, characterized in that a separately formed, refractory well nozzle is fixedly attached to the said plate assembly on the upstream side thereof, the said nozzle having at its upstream end an external location surface adapted for sealing engagement in the pour opening of the wall of the said vessel. Also in accordance with the invention there is provided a sliding gate valve assembly as initially described and characterised in that a refractory well nozzle is fixedly attached to the upstream side of the stationary plate structure in alignment with the flow orifice, with the nozzle extending in the upstream direction away from the stationary plate structure, and having at its upstream end a cylindrical external location surface for sealing engagement in the pour opening of the wall of the vessel. With the well nozzle fixedly attached to the stationary plate prior to the installation of the plate, the well nozzle serves as a guide to facilitate the installation operation. The invention will now be described in detail by way of example, with reference to the accompanying drawings, in which: Figure 1 is a transverse sectional view of a furnace with a sliding gate valve incorporating refractory plate structures in accordance with the invention; Figure 1a is an enlarged sectional view taken from location 1a on Figure 1 and showing the relationship between the end of the collector and the pour tube; Figures 2L and 2R are a composite exploded view of the subject valve with 2L representing the left-hand portion of the illustration and 2R representing the right-hand portion of the illustration; Figure 3 is an elevational view of the sliding gate assembly upstream face; Figure 4 is a transverse sectional view of the sliding gate assembly taken along section line 4-4 of Figure 3 and in the same scale of Figure 3; Figure 5 is a perspective view of the slide gate collector insert; Figure 6 is an elevational view of the casting for the slide gate showing the upstream face; Figure 7 is a transverse sectional view of the slide gate casting taken along section line 7-7 of Figure 6; Figure 8 is an elevational view of the slide gate casting showing the downstream face; Figure 9 is a perspective view of the collector tube; Figure 10 is an elevational view of the slide gate refractory insert; Figure 11 is a side view of the slide gate refractory insert shown in Figure 10; Figure 12 is an upstream face view of the stationary plate assembly; Figure 13 is a transverse sectional view of the stationary plate taken along section line 13-13 of Figure 12; Figure 14 is an upstream face view of the stationary plate frame only; Figure 15 is a transverse sectional view of the stationary plate frame taken along section line 15-15 of Figure 14. Figure 16 is a downstream face view of the stationary plate frame only; Figure 17 is a perspective view of the stationary plate insert drawn to an enlarged scale; Figure 18 is a perspective sectional view of the well nozzle drawn to a larger scale; Figure 19 is a downstream face view of the heat shield assembly. Figure 20 is a transverse sectional view of the built-up heat shield taken along line 20-20 of Figure 19, and Figure 21 is a detail section of the valve orifice similar to Figure 1 drawn to a larger scale showing an alternative construction well nozzle. Valve Assembly Etc. The valve assembly illustrated in Figures 1, 1A, 2L and 2R, the slide gate assembly illustrated in Figs. 3 to 11 and the heat shield and nozzle assembly illustrated in Figures 19 and 20, are fully described in the specification of the parent European Patent Application publication number 0120695 A2 to which reference is hereby directed. Stationary Plate The stationary plate is shown in Figures 12-17 inclusive. The stationary plate 20 is symmetrical about the metal flow opening, even though the sliding gate 21 is asymmetrical about the flow opening therethrough. As will be appreciated from the reinforcing construction of the stationary plate 20 it is provided to give full support to the pressure from the carrier spring pads 35 in all positions of travel of the slide gate 21 and the slide gate carrier 22. The metal stationary plate casing 90 is provided with a peripheral skirt 91 upstanding from its base. Centrally of the stationary plate an orifice insert 92 is disposed in a bed of monolithic refractory 93 with an annular insert lock groove 94 so positioned for interlocking the insert in the refractory bed 93 within the frame 90. Knockout holes 95 are provided at opposed positions in the base of frame 90, and each is formed with an inturned lock ring 96 that serves to anchor the refractory bed 93 within the frame. By the cooperation between the central opening in the base of frame 90 and the formed refractory bed 93 a well nozzle stepped seat 98 is provided centrally of the stationary plate 90, and terminates in one face of the stationary plate orifice insert 92. Threaded bores 99 are provided in the reinforcing rings 97 which surround the knockout holes 95. The bores 99 are threaded to receive funnels useful in casting monolithic refractory 93 into the stationary plate 20. As shown particularly in Figures 13 and 18, a preferred construction of well nozzle 19 is provided which rests atop the well nozzle seat 98 within the stationary plate frame 90. A locking assembly 105 is provided to secure the well nozzle 19 to the stationary plate 20. More specifically, a clamp washer 106 is secured by means of mount threads 107 in the stationary plate 90 through the medium of the washer mount screw 108. The washer 106 then is secured into the crescent-shaped recess that forms a washer lock 109 in the refractory of the well nozzle 19. Such locking arrangements are disposed on circumferential spacing about the periphery of the nozzle 19. Once this locking has taken place, the well nozzle 19 becomes fixed to the stationary plate frame 90 so that it can be installed in the valve upon installation of the stationary plate. In this way, the taper 110 on the block nozzle 19 is accurately secured in mating engagement with a mating taper 111 (see Figure 1) in the outer tap hole block 18 within the refractory 14 of the furnace 12 thereby avoiding sealing problems that would otherwise be occasioned by a blind assembly operation. The alternative construction of the well nozzle 19 is shown in Figure 21 , where the alternate refractory nozzle structure 104 is encased within a metal well nozzle frame 100, and includes a well nozzle ring 101 forming a shoulder which is lockingly engaged within a bored opening in the mounting plate, and secured in position by means of the well nozzle mortar 102, again as shown in Figure 21. In both constructions the well nozzle provides at its upstream end a cylindrical external location surface for sealing engagement in the pour opening of the wall of the vessel. As shown in Figure 1, the top plate is secured in place on the mounting plate 40 by positioning members that include top plate retaining pins 42 and restraint 43. Remanufacture As the stationary plate 20 and slide gates 21 are worn, they may be remanufactured and their respective frames reclaimed. As shown in Figure 4 primarily, a mandrel or press can engage the monolithic collector end 84, while at the same time a mandrel is inserted in the knockout hole 65. The combined pressures removes the collector insert 29 and the face insert 70. Thereafter by tapping or shaking, the balance of the monlithic cast material 80 may be removed. Similarly, when the stationary plate 21 is to be remanufactured, mandrels are provided to press on the knockout holes 95 at the same time a central mandrel engages the stationary plate orifice insert 92. The casting spaces mount 66 of the sliding gate 21 as shown in Figures 6 and 7 permits the insertion of a spacer to support the insert 70. The four circumferentially spaced spacer bores 99 about each reinforcing ring 97 in the top plate frame 90 are adapted for connection with a pouring spout that serves as sprews for supplying the castable material to the plate frame during fabrication. Lifting holes 87 may be optionally provided in the stationary plate in the same fashion as the holes 86 are provided in the sliding gate. Summary As described in EP-A2-0120695, the furnace valve 10 as shown is modified by means of an adaptor 11 to accommodate it to a furnace 12 in which the side tap is at an angle to the vertical. Lifting eyes 44 are provided on the frame assembly 36 so that the entire valve 10 can be removed. In cases where the valves 10 are to be always removed in their entirety, the hinge assembly 45 and the latch assembly 50 may be modified and simplified to a simple clamp. In the valve 10 as shown, however, the hinge assembly 45 and latch assembly 50 are shown to illustrate that the valve can be used in either mode when the refractory is replaced while the valve 10 is on the furnace 12, or in the event it is removed.

Claims: A refractory plate assembly adapted for use as the stationary plate of a sliding gate valve for controlling the discharge of molten metal from a metal furnace or like vessel, the said assembly comprising a metallic casing (90) housing a body of refractory material (20), the casing and the said body having aligned flow apertures therethrough, characterized in that a separately formed, refractory well nozzle (19) is fixedly attached to the said plate assembly (20, 90) on the upstream side thereof, the said nozzle (19) having at its upstream end an external location surface adapted for sealing engagement in the pour opening of the wall of the said vessel. A sliding gate valve assembly for controlling the flow of molten metal from the pour opening of a vessel, including a housing (36) mounted in use on said vessel, a stationary refractory plate (20) in said housing having a flow passage in open communication with said vessel pour opening, an orificed refractory slide gate (21) movably mounted in said housing in pressure-sealed, face-to-face relation with said stationary plate and means (25) for moving said slide gate with respect to said stationary plate to place the orifice therein into and out of registry with the stationary plate flow passage, the said stationary plate structure including a body of refractory material having a flow orifice and having a metal casing, characterized in that a refractory well nozzle (19) is fixedly attached to the upstream side of the stationary plate structure (90,93) in alignment with the flow orifice, with the nozzle (19) extending in the upstream direction away from the stationary plate structure, and having at its upstream end a cylindrical external location surface for sealing engagement in the pour opening of the wall of the vessel. An assembly according to claim 1 or 2, characterized in that said nozzle (19) comprises a plurality of recesses (109) formed at spaced locations about the exterior surface of said well nozzle (19) and is attached to the stationary plate structure (90,93) by a plurality of connectors (105) releasably connected to said casing (90) and having locking heads (106) engageable with the respective well nozzle recesses (109). An assembly according to claim 1, 2 or 3, in which said vessel pour opening contains a tap hole block (18), characterized in that said tap hole block (18) contains a recess (110) for reception of the leading (upstream) end of said well nozzle (19) in use of the said assembly, and that said tap hole block recess and the end of said well nozzle are cooperatively formed for reception of a body of refractory cement to seal the interface therebetween. An assembly according to any preceding claim, characterized in that said body (93) of refractory material comprises a body of cast monolithic refractory material embedding a fired refractory insert (92) forming the flow passage through said plate, said insert being retained in said plate in end-to-end abutting relation with said well nozzle (19). An assembly according to claim 5, characterized in that said fired refractory insert (92) is an annular member having a recess (94) about its exterior surface, said recess being adapted to receive monolithic refractory material to lockingly retain said insert in said stationary plate. An assembly according to claim 4 including a mounting plate (40) for mounting said valve housing (36) to the vessel wall, characterized in that said mounting plate (40) contains a through opening for penetration by said well nozzle, an annular counterbore about said through opening on the side of said mounting plate facing said vessel wall defining a recess, said recess being filled with a refractory material (17) to establish a refractory-to-refractory butt joint with the end of said tap hole block (18). An assembly according to any preceding claim, characterized in that the well nozzle (19) is secured in a recessed seat (98) in the refractory body (90). An assembly according to any preceding claim, in combination with a vessel having a pour opening for the discharge of molten metal, characterized in that the pour opening is defined by a tap hole block (18) having a counterbore (110) about the pour opening and that the said location surface of the well nozzle (19) is sealingly located in the said counterbore.

Inventors: KING, PATRICK DANA
Applicants: USX ENGINEERS AND CONSULTANTS, INC.
Application year: 1984
Main classification: B22D41
IPC codes: B22D37, B22D11, F27D3, B22D41