GB2128519A

GB2128519A - Slide gate tundish flow control

Info

Publication number: GB2128519A
Application number: GB08322502A
Authority: GB
Inventors: Dennis W Miles; David A Waters
Original assignee: Southwire Co LLC
Current assignee: Southwire Co LLC
Priority date: 1982-08-27
Filing date: 1983-08-22
Publication date: 1984-05-02
Also published as: BE897514A; GB2128519B; GB8322502D0; CA1197065A

Abstract

A slide gate flow control valve, pour spout (20) and spout mounting arrangement are disclosed wherein accurate molten metal flow is provided along with a rapid spout replacement method. The valve comprises inner and outer plates (12, 14) and an interposed gate member (13) forming a sandwich bolted (15, 16) directly to the tundish (11). The spout (20) is mounted on the outer valve plate (14) by quick-release fasteners (18, 19) so that the spout can be changed quickly when the valve is closed. <IMAGE>

Description

SPECIFICATION Slide gate tundish flow control Technical Field The present invention relates to the continuous casting arts, and especially to tundish apparatus employing flow control means and spout means.

More particularly, this invention is intended to replace the tundish spout and flow control means of the metering pin type. Unlike conventional slide gate tundish valves, the embodiment of the present apparatus disclosed is adapted for tundish end-wall mounting in combination with a particular spout mounting method.

Background Art An important advance in the art of casting molten metals wherein the molten metal was poured via a tundish was made with the advent of refractory sliding gate valve assemblies. U.S.

patents number 3,997,090; 4,000,837; 4,003,561; 4,017,010; 4,037,762; 4,042,207; 4,051,589; 4,056,2174,063,668; 4,076,153; 4,076,1 54; 4,077,457; 4,077,552; 4,079,869; 4,091,971; 4,096,976; 4,108,675; 4,116,372; and 4,131,21 9 are illustrative of the prior art, indicating a relatively crowded art. Other patents of interest include U.S. patents number 4,222,506; 4,227,630; 4,234,036; and 4,257,542. Generally, the foregoing describe various arrangements showing a sliding gate valve assembly intended for use in controlling the flow of molten metals in which an apertured sliding gate member is used to open and close a molten metal flow path in which the sliding gate member is composed of a refractory material.Straight nozzles are always included to direct the flow of molten metal; they are generally of a rather short length in comparison to their diameters and are generally further characterized in that they are relatively permanent elements of the flow control apparatus, not intended for easy removal and replacement. Such a configuration is quite satisfactory for the intended uses of the prior art, where the molten metals are discharged into large ladles, large molds, or tundishes from which the metal flow is further directed to one or more casting molds. Such apparatus is unsuitable to situations where the tundish nozzie must intrude into a small casting mold cross-section at complex angles and still remain capable of movement, as by manipulating the tundish.

Disclosure of Invention The present invention contemplates a threeelement slide gate control valve apparatus sealingly engaged to a panel member portion of a tundish or the like, wherein the three elements each have a major aperture providing communication between the tundish and the valve outlet such that the molten metal flowing out of the tundish may be controlled as to the flow rate by restriction of the aperture area through which the metal flows. The three elements are generally planar, with the first and third being fixed in position and the second being movable therebetween such as by a fluid cylinder or other equivalent manipulator means.The third or outer element includes quick release fastener means by which a spout mounting plate may be rapidly removed and replaced; the spout mounting plate fits over the slide gate apparatus such that the spout aperture (and thus the spout entrance) communicates with the tundish through the flow control valve. The spout may be rapidly changed by actuating the sliding member to interrupt molten metal flow, then the quick release fastener means are released, freeing the old spout by freeing the spout mounting plate. The old spout and its mounting plate are removed and replaced by a new spout and mounting plate assembly. The quick release fasteners are then replaced, the slide gate path is opened, and operations recommenced.

It is contemplated by this invention that a permeable plug area may be incorporated into the sliding member to permit interposing a permeable material between the two fixed elements of the slide gate valve such that when a short term interruption is required, a gas (such as nitrogen, argon, or oxygen) may be bubbled through the permeable material to avoid unwanted metal solidification in the flow control apparatus. In an alternative embodiment, multiple positions may be selected such that the sliding gate element may present different sized communicating passageways or combinations thereof with permeable metal flow passageway obstructions through which the gas may pass.

A tapered flat cotter key inserted in an elongated eye in the spout mounting plate fastening pin, for example, is one of many quick release fasteners which may be used to secure the spout mounting plate. Of course, the fastening pin is preferably attached to the fixed portion of the slide gate valve, the tundish, or both, as desired.

Brief Description of the Drawings Fig. 1 is a plan view of the apparatus comprising the present invention; and Fig. 2 is an end elevation view of a tundish apparatus incorporating the present invention.

Best Mode of Carrying out the Invention Turning now to Fig. 1 the slide gate tundish flow control apparatus 10 may be seen in detail in a partial plan view. The tundish 11 is seen in a configuration in which the molten metal contained therein is permitted to pass through an aperture 22 in an end or side wall of the tundish 11, which wall is in this example substantially vertical. It is to be understood that the mechanism of the invention is readily adaptable to other side or bottom walls or walls not substantially either vertical or horizontal.

The slide gate mechanism as shown comprises first plate 12, second plate 13, clevis 21, and fasteners 1 5 and 1 6. First and second plates 12,14 individually have major apertures therethrough 23, 27, while slide gate 13 may have at least one and preferably a plurality of apertures 24, 25, 26, which may be tapered or otherwise restricted in cross-section (not shown) or filled with a gas permeable material which is molten metals impermeable. This invention contemplates that the slide gate may be adapted such that the aperture or apertures are arranged to provide for manipulation thereof in either a linear or rotary fashion.

A tundish spout 20 is mounted securely to mounting plate 17, in which mounting plate aperture 28 communicates with spout passageway 29 to provide free movement of the molten metal therethrough.

First plate 12 is maintained in sealing engagement with tundish 11 as is hereinafter described. Second plate 14 is urged into contact with slide gate 1 3 by fasteners 1 5, 1 6 which may as desired be spring loaded (not shown). This may be accomplished by including compression springs between the heads of fasteners 1 5, 16 and second plate 14 to permit a modest degree of free relative movement between plates 12, 14 and slide gate 13 while maintaining sealing contact along the molten metal path. The apertures 27, 23 of plates 14 and 12 are maintained in constant, fixed coaxial alignment with tundish aperture 22.

A plurality of bolt fasteners extend through plates 14, 12 into the tundish 11 wall to ensure maintenance of this coaxial alignment only two of which 1 5, 1 6 are shown in this view. As shown in this view, the slide gate 13 includes a plurality of major apertures which can be manipulated into coaxial alignment with the spout-to-tundish passageway through manipulation of slide gate 1 3 by clevis 21 which is affixed to slide gate 13. In contemplated substitute embodiments, the slide gate 1 3 may be rotated about a point in a circular manner to position the gate as desired.

The spout 20 and spout mounting arrangement on plate 17 over alignment/quick-release fastening eye pins 18, 19 is especially useful in the configuration disclosed in this document, as spout changes have been discovered to be inconvenient according to prior art mounting methods, and due to the peculiar operating conditions in small cross section casting on machines having moving narrow mold entry approaches, spouts may require relatively frequent replacement. The spout mounting plate 1 7 includes a major metal flow aperture 28 and at least two mounting pin apertures through which quick release fasteners such as guide and mounting eye pins 1 8, 1 9 protrude.The eye pins have elongated rectangular eyes (30) therein adapted to receive tapered cotter keys such that the spout mounting plate 17 may be sealingly and securely fastened to the outer slide gate plate 1 4.

The tapered cotter keys are driven into the elongated eye slot (30) of the eye pins 18, 19 firmly, as with a hammer, to achieve the foregoing sealing engagement.

Spout replacement is rapid and efficient; the slide gate 1 3 is actuated to block molten metal flow therethrough, either by a refractory area of the gate or by a gas-permeable material through which a stirring gas may be bubbled, then the tapered keys are tapped free with hammer. The spout 20 and its mounting plate 1 7 are easily removed, a replacement spout 20 and mounting plate 21 placed over the eye pins, and the tapered cotter keys inserted into the elongated eyes (30) and hammered gently but firmly in place to lock the mounting plate 1 7 in operating position. The slide gate 1 3 is then actuated to permit molten metal flow, and casting may be resumed. The arrangement disclosed by this invention permits the entire spout change operation to be performed extremely rapidly.

Referring now to Fig. 2 an end view of a typical tundish 11 having the slide gate tundish flow control apparatus 10 of the present invention mounted thereon is shown. Note that a portion of the pouring spout 20 is deleted for clarity of certain fastener parts otherwise hidden from view.

The outer, or second plate 14 of the slide gate valve is shown, which is fastened in place by a plurality of fastener means 15, 1 6 such as threaded fasteners or the like, only two of which are shown; any larger number may be used as required. The spout mounting plate 1 7, shown as circular but which may be of any convenient shape, is attached to second plate 14 by means of a plurality (two are shown for example) of quick release fasteners. These may be of any desired type, such as threaded, twist-to-lock, or (as shown) eyepins 1 8, 1 9 having elongated rectangular eyes (30, Fig. 1) into which tapered cotter keys 31 are tapped into place, as shown.

The slide gate, hidden from view in this figure, includes a clevis eye 21 attached thereto for manipulation thereof. A fluid operated cylinder 35 attached to the front of tundish 11 includes a rod 34 and rod eye 33 which rod eye is pivotably attached within the clevis bifurcations by a pin 32.

Note that this arrangement is exemplary in nature and not intended to limit the configuration of the invention. For example, an alternate arrangement might include manual or motor-driven manipulation means. In this configuration a slide gate is shown which is linearly operated; while in alternate configurations the slide gate may be operated in a rotary fashion to maneuver the desired face, element, or aperture of the slide gate into the desired position in the molten metal flow path. The various elements in contact with the molten metal may be formed of refractory material or may be protected with refractory coatings.

Spout change is effected by operating the slide gate 1 3 (shown in Fig. 1) into the closed position, or into a slide gate position permitting a gas to be bubbled through a gas-permeabie element and in which molten metal flow is stopped. The tapered cotter keys (31, etc.) are dislodged from their respective eye pin 1 8, 1 9 apertures (30, etc.) freeing the spout mounting plate 1 7 for removal.

The spout mounting plate 17, to which the spout 20 is mounted, is removed by extracting same from mounting eye pins 18, 1 9. A new spout and mounting plate is guided into place over eye pins 1 8, 1 9 and tapered cotter keys 32 are inserted therein to lock the new spout 20 and mounting plate 1 7 in place.

While the foregoing description of the present invention is related in terms of molten metal flow control in the metallurgical arts, it is clear that with only minor changes and simple experimentation within the range of skills possessed by an artisan, the invention is adaptable for use with other flowable high temperature materials.

Industrial Applicability The slide gate flow control apparatus as herein described is useful in the high temperature flowable materials arts, such as the metal casting arts, and more particularly in those situations where accurate molten metal flow control and relatively frequent spout replacement are required.

Frequent spout replacement is often required with continuous casting apparatus wherein one or more of the casting mold surfaces moves in contact with the solidifying metal, and where the mold cross section is small, where spout manipulation is desired, and/or where high temperature metals are being cast.

Claims

1. A molten metal tundish sliding gate flow control apparatus comprising: a. tundish means for holding molten metal; b. a first, fixed position plate having a first surface thereof in sealing contact with said tundish, a second surface and having at least one major aperture therethrough, an outer second, fixed position plate having at least one major aperture therethrough, and a sliding gate means having an aperture therethrough, said sliding gate means being disposed between said first and second plates for control of the flow of molten metal from the tundish; c. spout means having an internal passageway therethrough for directing the metal flow, said spout means being attached to a spout mounting plate means; and d. fastener means for detachably mounting said spout mounting plate to said second fixed position plate.

2. In a molten metal tundish sliding gate flow control mechanism comprising: a. a tundish means for holding molten metal; b. a mechanism mounted to said tundish and including inner and outer, fixed position plates and a sliding gate therebetween, said slide gate flow control mechanism being adapted to regulate the flow of molten metal therethrough; c. spout means having an internal passageway therethrough for directing the metal flow, said spout means being attached to a spout mounting plate means; d. fastener means for detachably mounting said spout mounting plate in sealing engagement with said outer slide gate mechanism fixed position plate.

3. In a molten metal tundish system, a sliding gate flow control apparatus comprising: a. at least three panel members joined to form a tundish means for holding flowable molten metal, including at least one panel member having an aperture therein; b. a first plate means having a major aperture for molten metal flow and a plurality of minor apertures therethrough, surrounding said major aperture, said plate being in sealing contact with said first panel member and the major aperture being substantially coaxial with said tundish panel member aperture;; c. an outer second plate means having a major aperture for molten metal flow and a first group and a second group of minor apertures therethrough surrounding said major aperture, said second plate means being spaced apart from and parallel to said first plate means and disposed such that all the apertures of the first plate means are coaxial with the major aperture and the first group of apertures of the second plate means; d. a spout means having an internal passageway therethrough for directing molten metal flow, said spout means being attached to a mounting plate having a major aperture communicating with said spout means passageway for molten metal flow and having a plurality of minor apertures spaced to match the second group of minor apertures in the second plate means;; e. fastener means to reieasably attach the spout mounting plate to said second plate means; f. fastener means for releasably securing said second plate means in a parallel reiationship to said first plate means and to said tundish panel member; g. slide gate means having at least one aperture therethrough, said slide gate means having an aperture therethrough and being sealingly interposed between said first and second plate means and between the fastener means securing the first and second plate means to each other and to said tundish panel member such that said slide gate means aperture may be displaced to a closed position from a position coaxial with the major apertures of said first and second detachable stationary plate means permitting molten metal flow; and h. manipulating means to place and displace said slide gate means from a first position such that the slide gate aperture is coaxial with the major apertures of the first and second plate means to permit molten metal flow therethrough, through an intermediary position in which the flow of metal is restricted to a third position in which molten metal flow is completely stopped.

4. Apparatus as in Claims 1,2 or 3 in which the slide gate means includes a plurality of apertures therethrough.

5. Apparatus as in Claims 1,2, or 3 in which the slide gate means includes at least one aperture therethrough which is tapered from its first, inlet area to its second, outlet area to restrict the flow of molten metal therethrough.

6. Apparatus as in Claim 1,2, or 3 in which at least one aperture therethrough is restricted as to area and is substantially untapered.

7. Apparatus as in Claims 1 , 2, or 3 in which the slide gate means includes at least one aperture therethrough which is gas permeable and which is molten metal impermeable.

8. Apparatus as in Claims 1, 2 or 3 in which the molten metal flow control path begins through an aperture in a substantially vertical wall of the tundish.

9. Apparatus as in Claims 1,2, or 3 in which the spout mounting plate means is substantially vertical.

10. Apparatus as in Claims 1,2, or 3 in which the spout means is bent along its molten metal flow path.

11. Apparatus as in Claims 1, 2, or 3 in which the spout means is replaceable on the spout mounting plate means.

12. Apparatus as in Claim 1,2, or 3 in which the spout means passageway is substantially longer than the internal diameter of the spout passageway.

13. Apparatus as in Claim 1, 2, or 3 further characterized by spring means resiliently urging the outer plate against the sliding gate means and in turn the sliding gate means against the first, inner plate to seal the parallel surfaces of the flow control apparatus.

14. Apparatus as in Claims 1,2, or 3 in which the slide gate means is linearly actuated.

1 5. Apparatus as in any of Claims 1 to 13, in which the slide gate means is adapted to at least partiai rotary actuation.

1 6. Apparatus as in any of Claims 1 to 1 5, in which the spout mounting plate fasteners are of the twist to lock quick release type.

17. Apparatus as in any of Claims 1 to 15, in which the spout mounting plate fasteners are quick release fasteners of the eyepin and tapered key type.

1 8. A sliding gate flow control and spout assembly for a molten metal tundish, substantially as herein described with reference to the accompanying drawings.