US3786969A - Sliding-gate closure construction for bottom-pour vessels - Google Patents

Abstract

A slidable gate construction for use as a closure on a bottompour vessel, such as a ladle or tundish used for pouring liquid metal. The novel feature is that the upper face of the gate is convex when viewed in cross section. The underface of the top plate has a mating concave face.

Description

United States Patent [191 Kelly [45] Jan. 22, 1974 I SLIDING-GATE CLOSURE CONSTRUCTION FOR BOTTOM-POUR VESSELS [75] Inventor: Calvin E. Kelly, Franklin Twp.,

Westmoreland County, Pa.

[73] Assignee: United States Steel Corporation [22] Filed: Apr. 17, 1972 [21] Appl. No.: 244,518

[52] US. Cl 1. 222/561, 222/537, 222/DIG. 7 [51] Int. Cl B65d 47/00 [58] Field of Search... 222/561, 562, 563, 531, 560, 222/516, 517, 511, 559, 275, 276, DIG. 7,

[56] References Cited UNITED STATES PATENTS 2,916,190 12/1959 Furn 222/517 1,960,393 5/1934 Otten 222/556 3,685,707 8/1972 Shapland 222/559 3,436,023 4/1969 Thalmann 222/DIG. 7 3,228,574 1/1966 Patch 222/559 3,409,189 Il/l968 McKeand... 222/561 2,791,814 5/1957 Villela 222/559 3,685,705 8/1972 Cessna 222/561 3,623,541 11/1969 Schmitz 222/556 2,265,154 1I/1941 Erb 222/559 427,635 5/1890 Sutton 222/561 Primary ExaminerRobert B. Reeves Assistant Examiner-H. Grant Skaggs, Jr. Attorney, Agent, or Firm-Walter P. Wood [57] ABSTRACT A slidable gate construction for use as a closure on a bottom-pour vessel, such as a ladle or tundish used for pouring liquid metal. The novel feature is that the upper face of the gate is convex when viewed in cross section. The underface of the top plate has a mating concave face.

4 Claims, 4 Drawing Figures PATENTEUJANZZW I 3.786.969

' sum 1 or 2 PATENIED JAN 22l974 SHEEI 2 BF 2 SLIDING-GATE CLOSURE CONSTRUCTION FOR BOTTOM-POUR VESSELS This invention relates to an improved slidable gate construction for use as a closure on a bottom-pour vessel.

Although my invention is not thus limited, my gate construction is particularly useful as applied to vessels for pouring liquid metal, for example a ladle or a tundish. Such vessels have an outlet in the bottom wall through which liquid metal is poured into a receiving vessel. It is known to equip the pouring vessel with a slidable gate mounted on the underside of the bottom wall for controlling flow of metal through the outlet. Gates used heretofore have had flat upper surfaces, at least initially. Sometimes the gate may warp in use and acquire a curvature, but this is unintentional.

Heretofore various means have been employed for holding a flat gate in contact with a top plate thereabove. Shapland Reissue U.S. Pat. No. 27,237 and several later patents on improvements thereto show spring-pressed levers which engage the bottom of the gate along its side edges. Shapland application Ser. No. 150,585, filed June 7, 1971, shows an arrangement of coil springs surrounding the vessel outlet. Grosko et al. U.S. Pat. No. 3,604,603 shows inflated flexible tubes which engage the bottom of the gate along its side edges. Others, such as Fichera U.S. Pat. No. 3,454,201, omit the springs altogether and hold the gate rigidly as with screws. The flat gate leads to disadvantages with any of these arrangements. It is difficult to obtain uniform pressure on a flat surface from two remote edges. Two abutting flat surfaces are prone to slip from side to side in the absence of external guide means, wherefore it is difficult to position the gate orifice precisely with respect to the vessel outlet. Flat plates also require subsequent grinding after casting to insure flatness, thus adding to the cost.

An object of the present invention is to provide improved slidable gate construction in which the mating surfaces of the gate and top plate are convex and concave respectively to overcome the disadvantages of flat gates and top plates.

In the drawings:

FIG. 1 is a cross-sectional view of the bottom portion of a vessel equipped with a top plate and slidable gate constructed in accordance with my invention;

FIG. 2 is a diagrammatic longitudinal sectional view of the top plate and gate on line II-II of FIG. 1;

FIG. 3 is a diagrammatic cross-sectional view of the top plate and gate; and

FIG. 4 is a diagrammatic cross-sectional view similar to FIG. 3, but showing a modification.

FIG. 1 shows a portion of a conventional bottompour vessel 10. A top plate 12 and a slidable gate 13 constructed in accordance with my invention and hereinafter described are mounted beneath the bottom wall of the vessel to control flow of material therefrom. The support means for the top plate and gate can be any of various known types. The means illustrated includes a mounting plate 14 fixed to the bottom of the vessel, hinge brackets 15 depending from the mounting plate, and a frame 16 hinged at one side to the brackets. The opposite side of frame 16 is attached to the mounting plate 14 with bolts 17. The bolt heads can be disengaged from the mounting plate by rotating the bolts a quarter turn. This construction enables frame 16 to swing downwardly, whereby the top plate and gate can be removed and replaced readily. Frame 16 carries rails 18 on which gate 13 is slidably supported along its opposite side edges. The bolts 17 carry compression springs 19 which urge the frame, rails, gate and top plate upwardly into a close-fitting relation. The top plate has the usual orifice 20 aligned with the vessel outlet, and is held in place by any suitable means (not shown) engaging its side and end edges.

Gate 13 is shown as having an orifice 21 and a depending nozzle 22. The gate and nozzle are formed of a refractory body encased in a metal frame. The gate illustrated is of the reciprocating type, in which a solid portion of its area can be moved into alignment with the orifice 20 to close off flow. Alternatively the gate may be of the slide-through type which is replaced by a blank to close off flow. The gate is equipped with conventional hydraulic means or the like (not shown) to propel it along the rails, as shown in the patents hereinbefore referred to.

In accordance with my invention, the upper face of gate 13 is convex when viewed in cross section, that is, in a plane which extends at right angles to the direction it travels-in opening and closing, as best shown in FIG. 2. The underface of the top plate 12 is concave to mate with the convex face of the gate. The bottom face of the gate is essentially flat except for the nozzle 22. In the form shown in FIG. 3, the convex and concave faces are formed on arcs of equal radii R. FIG. 4 shows a modification in which concave surface of the top plate 1211 has a larger radius R than the radius R of the convex surface of the gate 13a. Ideally the convex arc of the gate would be a parabola, since a parabola would afford maximum strength and resistance to deflection. Since a parabolic surface is too difficult to construct, I prefer to compromise by forming the convex surface on a circular arc. The radius of the arc is in the range of about 6 to 24 inches.

Forces applied to the gate near its side edges are effectively transmitted to the mid portion of the gate where it abuts the top plate. Stiffness of the gate in the transverse direction is proportional to the cube of the thickness at the center. Hence the increased thickness compared with a flat gate produces a large resistance against deflection from the static head of material in the vessel.

I claim:

1. In a slidable gate closure construction for controlling discharge of liquid metal from a ladle or a tundish having an outlet in its bottom wall, which construction includes a refractory top plate having an orifice aligned with said outlet, a refractory gate abutting the underside of said top plate and slidable with respect thereto to open and close said orifice, and means engaging said gate along its side edges for supporting both said top plate and said gate on the underside of a vessel, the improvement in which the upper face of said gate is convex as viewed in a cross section taken in a plane transversely of the direction of gate travel, and appears straight as viewed in a longitudinal section taken in a plane parallel with the direction of gate travel, and said top plate has a mating concave lower face, whereby forces applied to the gate along its side edges are effectively transmitted to the mid portion of the gate where v in the range of about 6 to 24 inches.

4. An improvement as defined in claim 1 in which said gate carries a nozzle depending from its lower face, but the lower face of said gate is essentially flat apart from said nozzle.

Claims (4)

1. In a slidable gate closure construction for controlling discharge of liquid metal from a ladle or a tundish having an outlet in its bottom wall, which construction includes a refractory top plate having an orifice aligned with said outlet, a refractory gate abutting the underside of said top plate and slidable with respect thereto to open and close said orifice, and means engaging said gate along its side edges for supporting both said top plate and said gate on the underside of a vessel, the improvement in which the upper face of said gate is convex as viewed in a cross section taken in a plane transversely of the direction of gate travel, and appears straight as viewed in a longitudinal section taken in a plane parallel with the direction of gate travel, and said top plate has a mating concave lower face, whereby forces applied to the gate along its side edges are effectively transmitted to the mid portion of the gate where the gate abuts the top plate.

2. An improvement as defined in claim 1 in which said coNvex and concave faces are formed on arcs of approximately equal radii in the range of about 6 to 24 inches.

3. An improvement as defined in claim 1 in which said convex and concave faces are formed on arcs, with the radius of said concave face being greater than the radius of said convex face, the radius of each arc being in the range of about 6 to 24 inches.

4. An improvement as defined in claim 1 in which said gate carries a nozzle depending from its lower face, but the lower face of said gate is essentially flat apart from said nozzle.

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