Sliding closure unit with improved plate pressing structure

#The present invention relates to an improved slide gate or sliding closure unit for controlling the discharge of molten metal from an outlet nozzle of a metallurgical vessel, particularly a steel foundry ladle, the sliding closure unit being of the type including a stationary refractory plate having therethrough a discharge opening aligned with the outlet nozzle of the vessel, a stationary housing assembly for mounting the stationary refractory plate on the metallurgical vessel, a movable refractory plate having therethrough a discharge opening, the stationary and movable refractory plates having complementary, abutting relative sliding surfaces, a movable frame mounting the movable refractory plate for movement with respect to the stationary refractory plate to bring the discharge opening of the movable refractory plate into and out of alignment with the discharge opening of the stationary refractory plate, and means for pressing the movable refractory plate toward the stationary refractory plate to ensure sealing between the complementary, abutting relative sliding surfaces.

#Typically, such pressing means is in the form of spring loaded rocking or pivotable levers having support or contact members which are urged against, for example, guide tracks of the movable frame, thereby urging the movable frame and movable refractory plate toward the stationary refractory plate. These types of arrangements are disclosed in DE-AS 1,299,804 with respect to a movable refractory plate which is movable rectilinearly and in DE-OS 22 12 312 with respect to a movable refractory plate which is mounted for rotary movement. In such arrangements, the levers are mounted to extend generally perpendicularly to the direction of movement of the movable refractory plate. Thus, these levers are mounted with the support or contact ends beneath the movable frame and with opposite, spring-loaded ends extending outwardly therefrom. As a result of this arrangement, the overall sliding closure unit is of a relatively cumbersome design requiring a substantially large amount of space which only rarely is available. A further disadvantage of this conventional arrangement is that the levers are mounted in a manner which does not provide adequate stability to withstand the pressures necessary to ensure tight sealing between the two refractory plates.

#Additionally, Austrian Pat. No. 359,664 discloses a sliding closure unit having a rectilinearly movable frame guided on rollers between two rocker-type frames, each mounted to oscillate on a swing-out lever. Spring buffers and a cross brace are provided on free ends of the levers and, during clamping of the levers against a housing structure by means of snap closures, the spring buffers cause the movable refractory plate to be pressed sealingly against the stationary refractory plate. With this construction, the rocker-type frames provided externally of the movable frame result in a relatively wide and high overall structure. Additionally, the contact pressure by the spring buffers mounted on an end face of the unit is applied in an asymmetric and indirect fashion via the levers which are exposed to strong torsional forces.

#Other objects, features and advantages of the present invention will be apparent from the following detailed description of preferred embodiments thereof, with reference to the accompanying drawings, wherein:

#FIG. 1 is a longitudinal sectional view through a sliding closure unit according to the present invention, the movable refractory plate being rectilinearly movable;

#FIG. 2 is a plan view of a cover member shown in FIG. 1;

#With reference to FIGS. 1-3, a first embodiment of the present invention will be described. Thus, illustrated is a portion only of a bottom of a metallurgical vessel including an outer metal jacket 1 having inwardly thereof a refractory lining (not shown) having extending therethrough a perforated nozzle brick 2 into which extends a two-part inlet sleeve or nozzle 3 the outlet orifice or opening 4 of which forms an inlet into a sliding closure unit 5 according to the present invention.

#Such unit includes a stationary housing assembly including a housing member 6 removably fastened to metal jacket 1, a stationary refractory plate 7 mounted in housing member 6 and having a discharge opening 8 aligned with outlet orifice 4. A movable refractory plate 10 has therethrough a discharge opening 9 and is mounted against refractory plate 7 such that the two plates 7, 10 have complementary, abutting relative sliding surfaces. A movable frame 12 mounts movable refractory plate 10 for movement with respect to stationary refractory plate 7, for example by means of a power source 16 shown only schematically in FIG. 1. A refractory discharge nozzle 11 is mounted in abutment with movable refractory plate 10, for example by means of a bayonet connection illustrated somewhat schematically in FIG. 3. The housing assembly further includes a cover member 15 which is pivotally mounted on housing member 6 by means of hinges 13 and pivotal locking levers 14. The construction of the mounting of cover member 15 to housing member 6 is illustrated in the drawings and does not in and of itself constitute a portion of the present invention, but rather the invention of a copending U.S. application entitled "APPARATUS FOR RELIEVING THE PRESSURE OF CLAMPING SPRINGS IN A SLIDING CLOSURE UNIT", filed concurrently herewith by Hans Muller and assigned to the assignee of the present application. The disclosure of such copending application is incorporated herein by reference.

#Power source 16 moves frame 12 and movable refractory plate 10 rectilinearly, and this movement is guided within the housing assembly. The movable frame 12 and movable refractory plate 10 are urged toward the stationary refractory plate 7 to ensure a sealing contact between the complementary abutting sliding surfaces of the two plates, thereby to provide a satisfactory seal therebetween to prevent leakage therebetween of molten metal.