CA1340029C - Non-reversible sliding gate valve and method - Google Patents

Abstract

A method of and change to the lower portion of the slide gate to be asymmetrical in the gate loading direction such that altering the supporting loading rail portions of the frame on the mechanism to prevent loading of the gate in the incorrect orientation is disclosed. The frame for the existing sliding gate valve is asymmetrical about the gate change axis which thereby eliminates the requirement or left and righthanded frames to make left and righthanded mechanisms.
The method to change a mechanism from a left to a righthand load requires two additional parts. In this change the frame is changed to be asymmetrical and yet require only the same two additional parts to change from left to righthanded load. Left and righthand load is defined by the operator's position being the firing cylinder end of the mechanism with the operator facing the mechanism. A righthand load mechanism has the loading port on the operators right side. The lefthand load mechanism has the loading port on the left side. The sliding gate valve frame is to be modified so that the gate loading rail on the cylinder end on the righthand side of the mechanism is extended. This requires a righthand load to load the sliding gate with the long ledge towards the firing cylinder.
The same gate conformed by the method into a lefthand load valve assembly has the loading rail away from the cylinder extended on the lefthand side of the mechanism. This forces the gate to be loaded with the long ledge away from the firing cylinder during lefthanded loading. Thereby, a single frame with the asymmetrical loading port arrangements, yet otherwise symmetrical along the firing axis, enables a non-reversible sliding gate without the requirements of dedicated left and righthanded mechanism frame assemblies. The slide gate has asymmetrical loading ledges and preferably symmetrical throttling rails.

Description

13 ~ ù v ~
~ON--REVERSIBLE SI.IDING GATE VALVE, AND METHOD
Field of the Invent:ion:
3 The present invention relates to throttling tundish 4 valves of the type used in teeming metal, usually into a continuous caster, Patent: Nos. 4,415,10~1 and 4,545,512 are 6 exemplary of the environment in which the invention fin~s 7 utility.
8 Summary of the Prior Art:
9 The sliding gate for a throttling tundish valve has a symmetrica:L frame. The gate assembly is asymmetrical due to the 11 location of the offset teeming orifice. Reference Patent Nos.
12 4,415,103 and 4,545,512 for such environmen1.
13 The sliding gate may be loaded into the sliding gat;e 14 valve in two positions, with the teeming orifice towards the loading side or with the teeming orifice away from the loading 16 side. Some users have left and righthand mechanisms due t:o 17 clearances around the casting machine. Even with left and 18 righthand mechanisms the loading practice for any one shop is 19 normally consistent, that is, teeming orifice away or teeming orifice toward the loading side.
21 If a sliding gate is loaded improperly it creates a 22 significanlt potential safety hazard in that the controls are now 23 reversed and open is closed, and closed is open, for both the 24 manual ope:ration of the valve as well as the automatic operation.
Therefore, an emergency close off with the reversed gate wou]d 26 actually be a full open situation which could cause a malfunction 27 with an operator who was negligent in not recognizing the 28 reversal.
29 Schemes to prevent: improper loading of the valve have followed such lines as, pneumatic sensors to sense the location - 13~0~J~Q
:L of the teeming orifice in the gate, or markings on the gates, 2 etc. None of these are positive because none of them impedes the 3 improper loading of the sliding gate. The pneumatic sensor ~L system is very complex and definitely subject to maintenance and 'j reliability problems considering the environment in which it 6 operates.
,' The present invention is directed to a sliding gate that E~ blocks improper loading into the sliding gate valve and a sliding '~; gate valve for use with the modified sliding gate which allows loading in only one direc:tion. The sliding gate valve also 11 allows left and righthand mechanisms without two different frames 12 being required and without requiring left and righthand gates for 13 a specific customer.
l~L The existing sliding gate has a sheet metal frame which has a reduced cross-section area on the lower portion of the gate 16 to form the ledges referred to in U.S. Patent Nos. 4,415,103 and 1,l 4,545,512. In this lower portion of the gate the ledges are l~i symmetrical, thereby allowing the gate to be loaded into the 1" sliding gate valve in either direction.
Summary of the Invention:
2] The present invention relates to a method of and change 22 to the lower portion of the slide gate to be asymmetrical in the 23 gate loading direction such that altering the supporting loading 24~ rail portions of the frame on the mechanism will prevent loading 2 Fj of the gate in the incorrect orientation. The frame for the 2~i existing sliding gate valve is completely symmetrical about the 27 gate change and loading axes which thereby eliminates the 2~ requirement for left and righthanded frames to make left and 2SI righthanded mechanisms. The method to chanc3e a mechanism from a 13q'~029 ] left to a righthand load requires two additional parts. In this 2 change the frame is changed to be asymmetrical and yet require l only the same two additional parts to change from left to 4~ righthanded load. Left and righthand load is defined by the F; operator's position behind the firing cylinder end of the 6 mechanism ~ith the operator facing the mechanism. A righthand load mechanism has the loading port on the operators right side.
~ The lefthand load mechanism has the loading port on the left c~; side. The sliding gate valve frame is to be modified so that the gate loading rail on the cylinder end on the righthand side of 1] the mechanism is extended. This requires a righthand load to 12 load the sliding gate with the long ledge towards the firing 13 cylinder. the same gate valve conformed by- the method into the 14 lefthand load valve assembly has the loading rail away from the cylinder extended on the lefthand side of the mechanism. This 16 forces the gate to be loaded with the long ledge away from the 17 firing cylinder during lefthanded loading. Thereby, a single 18 frame with the asymmetrical loading port arrangements, yet 1~1 symmetrical along the firing axis, enables a non-reversible 2CI sliding gate without the requirements of dedicated left and 21 righthanded mechanism frame assemblies. The slide gate has 22 asymmetrical loading rails and preferably symmetrical throttling 23 rails. The space between the throttling rails is desirably 24 greater than the loading rails with gates conforming to this prevent another reversal in loading.
26 In view of the foregoing, it is a principal object of the 27 present invention to develop a slide gate for a tundish valve 28 which cannot be loaded improperly, and a modification for a 29 tundish valve to accommodate the same.

134~
:LIt is a further objective of the present invention to .' provide th~e above irreversible features at essentially no :~ additional cost to the manufacturer or the customer but with the 4 result of significantly improved safety characteristics.
';A further object of the present invention is to provide 6 the non-reversible tundish valve constnlction which is an inexpensive retrofit on existing valves such as exemplified in ~Patent No. 4 415 103 and then an inexpensive means for modifying C1; the frame and the slide gate to mate with the retrofitted valve 1() in an efficient fashion.
l:LBrief Description of the Drawinqs:
12Further objects and advantages of the present invention 1:3 will become apparent as the following description of an l~L illustrative embodiment proceeds, taken in conjunction with the 1'; accompanying illustrative drawings, in which:
16FIG. 1 is a longitudinal sectional view of a typical 1,7 tundish valve showing the slide gate in the position moving from 1~ left to right;
1'3FIG. 2 is a transverse sectional view taken along section 2() line 2-2 of FIG. 1 showing the slide gate in the shut-off 2:L position;
2.'FIG. 3 is a downward view taken along sèction line 3-3 of 23 FIG. 1 illustrating the slide gate being inserted from either 2~L side as an option, depending upon how the valve is rigged;
2';FIG. 4 is a side view of that portion of the frame shown 26 in FIG. 3 and illustrating a slide gate in the loading position;
21FIG. 5 is a view from underneath the frame shown in FIG.
2~ 4 and similarly illustrating the optional left/right entry 2'~ positions of the slide gate;

1 2 ~
:L FIG. 6 is an isometric view of the frame taken from an ;~ above posit.ion;
:3 FIG. 7 is a view of the frame comparable to FIG. 6 but 4 from an und.erneath position;
'; FIG. 8 is a plan view of the slide gate illustrating i:n 6 dotted lines the undercut on the rails for loading;
,7 FIG. 9 is a side view of the slide gate shown n FIG. 8 ~ illustrating the asymmetrical rail undercut;
9; FIG. 10 is an isometric view of the slide gate of FIGS. 8 1() and 9 and indicating the directions of feed and throttle with the 11 letters F and T, and showing the asymmetrical rails at the 12 righthand portion;
1:3 FIG. 11 is a plan view of the frame for the slide gate l~L excluding the refractory;
1'; FIG. 12 is a transverse sectional view of the frame shown 16 in FIG. 11 taken along section line 12-12 of FIG. 11 and 17 illustrating the emphasized undercut at the lower portion of the 1~3 asymmetrical rails;
1'3 FIG. 13 is an isometric view of the frame shown in FIGS.
2(l 11 and 12; and 2.L FIGS. 14 and 15 are plan views of the frame essentially 22 the same as FIG. 3, however, detailing the means by which the 23 valve can be altered from a lefthand feed to a righthand feed.
24 Detailed Description of a Preferred Embodiment:
2'; In FIGS. 1 and 2 of the drawings, there is shown a 26 sliding gate valve 10 adapted for installation in operative 2,' relation to the pour opening 12 in the lining 14 of a teeming 2~ vessel 16, such as a tundish or the like, for teeming molten 29 metal into the mold of a continuous caster (not shown. Where 134~
:L feasible, the reference numerals correspond to those used in ~) United States Patent No. 4,415,103. For further reference to 3 details of the valve, attention is directed to that patent.
~L Teeming is controlled by the manipulation of refractory slide 5 plates, that may be orificed as shown at 180 in FIG. 2. The 6 valve 10 also includes replaceable submerged pour tube assemblies .' 19 that form extensions of the valve for conducting the teemed ~i molten metal stream to a point below the surface of the metal in C~; a caster mold. The valve organization 10 is adapted for mounting lo to the vessel 16 by means of threaded connectors 20 extending l]L through ho:les 21 in the frame 22 attach.ing the same to the 12 mounting plate 23 which is, in turn, attached to the vessel b~
13 means of bolts that connect with a nut plate 24 underlying the l~L vessel lining 14. A heat insulating pad 26 formed of asbestos, or the like, may be interposed between the mounting plate 23 and 1~; the vessel 16.
1.7 As best shown in FIGS. 1 and 2, the mounting plate 23 is 1~ a generally flat metal plate having a central opening 28 for a 19 reception of the lower end 30 of the refractory material forming the vessel pour opening 12. The upper surface of the mountin~
21 plate 23 contains, along its side edges recesses 31 that 22 communicate with bolt holes 32 for reception of the connectors 2 23 and their associated nuts 34.
24~ The valve frame 22, formed essentially of a machined metal casti.ng stiffened by members 56 is best illustrated with 26 particular reference to FIGS. 6 and 7. This frame 22 contains 27 the operating parts of the valve organization and is adapted fo:r 2~ attachment to the mounting plate 23, or release therefrom, as an 2C~ assembled unit through connectors 20. The frame 22 comprises 1 ~AO029 three principle sections, indicated generally in FIGS. 6 and 7 as plate loading section 58, operating section 60 and plate discharge section 62. Adjacent the plate loading section 58 the frame 22 is attached, through connectors 20. The firing cylinder 68 ~FIG. 1) comprises a fluid operating cylinder 70 having a reciprocable piston positioning a piston rod 72 and a pusher 74. A second set of actuators, termed "throttling cylinders" are attached to the frame 22 adjacent the operating section 60 thereof ~see Figure 6). These actuators 76 (see FIG 2) are oppositely acting and are operated independently of the firing cylinder 68. They each comprise an operating cylinder 78 mounted to the frame by bracket 80. The cylinders 78 contain a reciprocable piston whose rod 83 bears against a laterally elongate push bar 86 which connects push pins 88 thar are guidingly received in openlngs 90 (FIG. 6) in the frame side wall and attac~ throttling rails 84 and 84' (Fig. 14) that operate to manipulate a slide plate disposed in the operating section 60 of the frame. Rail 84' is of a length shorter than rail 84 in order to accommodate passage of a plate through the loading section 58 of the frame.
The interior of the frame 22 is configured to define communicating paths of -travel for slide plates 17 or define communicating paths of travel for slide plates 17 and submerge~
pour tube holder assemblies 36 between the respective frame sections 58, 60 and 62. The loading section 58 of the frame 22 here described is defined by laterally extending guideways 92 and 94 adapted to pass slide plates 17, and submerged pour tube holder assemblies 36 re,pectively. The g~te guideway 92 (FIG. 7) ls vertically spaced from submerged pour tube holder guldeway 94 by oppositely extending gate loading rails 96 (short) and 96' (long) -that serve to support the slide plates that are loaded in the -valve. The bottom of guideway 94 is defined by a set of loading rails 98 of equal sizes that suppo.rt submerged pour tube holders 36 for loading.
It will be appreciated that frame 22, as depicted in FIGS. 1-14, is adapted for slide plate for submerged pour tube holder insertiGn from either the right or lefthand side by the provision of identical guideways 92' and 94' on the opposite side of the frame. Whe:n the guideways 92 and 94 are selected for use, those guideways indicated as 92' and 94' on the opposite side cf the fr.~me are closed by a stuffer member 100 (FIG. 14). Loading from the opposite side of the frame can be readily effected by moving the stuffer member 100 from guideways 92' and 94' to the opposite side of the frame where it will fi.ll the guideways 92 and 94.
The operating section 60 of the frame 22, as shown in FIG. 7, contains a rectangular opening 110 in the upper surface thereof for reception o:f a stationary refractory top plate 18 (see FIG. 2) whose cent:ral orifice 112 aligns with the pour opening 12 from the vessel and defines the inlet to the valve 10. Vertically spaced below the opening 110, the frame 22 is provided with oppositely spaced bases 114 (see FIG. 7) that cooperate with the uppe:r wall of the fram~ to define a cavity 115, as shown in FIG. 1. The bases 114 are provided with laterally threaded hole, 116 (FIG. 7) whish receive connectors 118 for mounting a series of spring biased levers 120 that l~40a~s operate to retain the submerged pour tube holder assembly 36, slide plate 17 and top plate 18 in surface-to-surface sealed relation. The levers 120 pivot upon rockers 122 retained by the connectors 118 and are spring biased by spring pins 124 movably mounted in holes 126 in the frame (see FI~f. 2).
As shown in FIG',. 2, 19 and 15, the throttling rails 84 and 84' are disposed in the frame 22 at substantially the same elevation as slide plate loading guideway 92. Rail 84 is longer than rail 84' extending substantially the full length of the frame interior. Rail 84', on the other h~nd, is shorter than rail 84 by an amount to permit passage of a slide plate 17 from the guideway 92 into po,ition with respect to pusher 74 upon loading of these member,. Rail 84 is further provided along that portion of its length that faces the guideway 92 with a plurality of longitudinally spaced magnets 142 here shown as being six four-pole permanent magnets, the function of which i, to prevent dislodgement of a slide plate 17 in the loaded, "ready" position.
The slide plates 17, top plate 18 and submerged pour tube holder assemblies 36 of the valve organization 10 each essentially comprises a refractory material encased in a metal frame. The slide plate assemblies utilized in the valve organization may be blank or imperforate or may contain a through opening 180 as the type shown at 17 in FI(-fS. 8 and 10. Blank plates 17' are employed to prevent metal t-low through the valve while orificed plates 17 are employed when it is desired to controllably pass molten metal through the valve as hereinafter described. Both slide plate assemblies a-e fabricated in a 1 ~40029 similar manner comprising a generally rectangular refractory plate 182 which is slightly longer in the throttle direction indicated as T in FIG. 10 than in the fee~ direction indicated as F. The plate 182 is mo:rtared within a metal casing 184 that encloses the peripheral sides of the plat~. The casing 184 is provided with a shoulde:r 186 intermediate its upper and lower edges for seating engagement on the throttling rails 84 and 84"
and for sliding engagement upon the gate loading rails 96 and 96 in the loading section 58 of the valve an~ the shoulders in the discharge section 62 thereof. The refractory plate 182 is formed at 188 with a mating shoulder conforming to that in the casing.
In accordance with the invention, and particularly as noted in FIGS. 8-13, it is important that the plate loading ledges which are in the direction of loading 200, 200/ be asymmetrical. That is to say one is a narrower ledge and the other is a wider ledge. In this fashion, it is impossible to reverse the slide gate member 17 when it is inserted into the valve frame such as illustrated in FIGS. 3 and 4. The plate loading ledges 200 are <,upported by the gate loading rails 96, 96' in the guideway 92, and since the gatl~ loading rails are longer and shorter, 96 and 96', then the plate loading ledges 200, 2"fO' must match up in order to be fed. Once fed into the frame 22/ the throttling rails 84, 84' are conformed to engage the feed ledges 201 and accommodate the tnrottling action. The distance between the two feeding ledges 201 is greater than the distance between the loading ledges 200, 200' to prevent loading on the feeding ledges 2()1 rather than on ~he loading ledges 20() 200'.

L~40029 l Therefore, in summary, utilizing a prior-art valve such 2 as shown in greater detail in U.S. Patent No. 4,415,103 the - 3 method to accommodate the present invention, requires primarily 4 modification of the loading rails 96, 96' and a reversal of the stuffer 100 (already provided for in the given structure).
6 Depending upon whether the operator has a lefthand or righthand 7 unit, and depending upon which direction is used for throttling, 8 the slide plates are selected and thus the slide plate 17 will 9 naturally be oriented in the proper direction, and the same direction always so that in the event of an automatic shutoff, 11 the activation is consistent.
12 The lower portion of the casing 190 is formed with an 13 enlarged radius curvature providing a guiding surface to enable 14 the respective slide plate assemblies when being moved by pusher 64 into the operating section 60 of the valve to be guidingly 16 urged up and over the upper edge of the submerged pour tube 17 holder assembly without causing damage to either member.
18 A typical commercial embodiment of the slide plat:e 19 assembly 17 is approximately 10.9 inches long in the feed direction F and 12.9 inches long in the throttling direction T
21 with the center of the opening 180 having a three inch diameter 22 being offset from the plate center point approximately 1.75 23 inches thereby providing about one-half inch of refractory 24 material between the holes 112 and 180 with the plate 17 in the shutoff position.
26 It will be understood that various changes in the 27 details, materials and arrangements of pc~rts which have been 28 herein described and illustrated in order to explain the nature 29 of the invention, may be made by those skilled in the art within 13~J;~329 1 the principle and scope of the invention as expressed in the 2 appended claims. The claims are addressed to the valve 3 apparatus, the method, and the sliding gate.

Claims (46)

1. A method of preventing reversibility of a slide gate having offset ledges and a teeming orifice in a valve which is loaded with a slide gate having loading rails and feed rails, offset loading edges, and a loading portion for loading said slide gate into the valve perpendicular to the axis of the feed rails and parallel to the axis of throttling comprising the steps of:
- forming asymmetrical ledges in parallel relationship to the underneath portion of a slide plate in the direction of loading, - positioning the loading rails in the valve to conform to the offset ledges in the slide plate in the direction of desired loading, - providing means for closing the loading portions of the valve opposite the portion in which loading is desired, - proportioning the loading rails for engaging the opposite underneath portions of the slide gate in perpendicular relationship to the feed rails, - and thereafter loading the slide gate into the valve.

2. In the method of claim 1 above, - offsetting the orifice in said slide plate along the direction of loading and throttling.

3. In the method of claim 2 above, - conforming the feed rails for feed and providing ledges for feed perpendicular to the direction of throttling which rails and ledges are in symmetrical relationship.

4. In the method of claim 3 above, -conforming the rails for feed and the ledges for feed of a lesser width than the wider of the two rails for loading and ledges for loading which are parallel to the direction of loading and throttling.

5. A slide gate comprising, in combination, - a frame of essentially rectangular configuration surrounding and retaining a refractory, - a refractory inserted interiorly of and secured to said frame, - said refractory having an orifice, - ledges in asymmetrical configuration underneath the frame and refractory at the edge portions thereof, parallel thereto and defining the direction of loading, - and ledges which are essentially in perpendicular relationship to the asymmetrical loading ledges defining the direction of feeding.

6. In the slide gate of claim 5, - said refractory orifice being offset along the intended axis of throttling.

7. In the slide gate of claim 5, - said ledges in the direction of feed being symmetrical in the direction of feed.

8. In the slide gate of claim 6, - said ledges in the direction of feed being symmetrical in the direction of feed.

9. In a full throttle tundish valve having a plurality of yieldable means, a top plate, a sliding plate, and a pour tube having a holder, said yieldable means engaging the downstream side of that plate portion of the submerged pour tube holder to apply sealing force to the submerged pour tube holder, the sliding gate, and the stationary top plate, a loading portion, a steeming and throttling portion perpendicular with the loading portion, the improvement comprising, - opposed rails in the loading portion of said tundish valve for engaging and loading a slide gate in the direction of loading, - said rails being asymmetrical when viewed from the direction of loading the slide gate to thereby accommodate a slide plate which has asymmetrical undercut ledges in the direction of loading, - and means for blocking off one end of the lefthand/righthand loading of said tundish valve, whereby the asymmetrical loading rails insure that a slide plate having an orifice only be loaded in to the valve in one configuration of the relationship of the orifice to the loading portion of the valve.

10. A method of preventing reversibility of a slide gate having an orifice in a valve having a loading direction and a feeding direction for the slide gate comprising the steps of, - fixing asymmetrical ledges in parallel relationship to the underneath portion of a slide plate in the direction of loading, - fixing the loading rails in that valve to conform to the offset ledges in the slide plate in the direction of desired loading, - closing the loading portions of the valve opposite the portion in which loading is desired, - and fixing rails for engaging the opposite underneath portions of the slide gate in perpendicular relationship to the rails of feed.

11. In the method of claim 10 above, - offsetting the orifice in said slide plate along the direction of loading and throttling.

12. In the method of claim 10 above, - securing the rails for feed and the ledges for feed perpendicular to the direction of throttling in symmetrical relationship.

13. A slide gate with a loading and feeding direction for a slide plate essentially perpendicular to each other comprising, in combination, - a frame of essentially rectangular configuration surrounding and retaining a refractory, - a refractory inserted interiorly of and secured to said frame, - said refractory having an orifice, - ledges of unequal width on opposing edge portions below the top surface of the slide gate parallel to the axis in the direction of loading, - and ledges of equal or near equal width on opposing edge portions below the top surface of the slide gate parallel to the axis in the direction of feed which is essentially perpendicular to the axis in the direction of loading.

14. In the slide gate of claim 13, - said ledges parallel to the axis in the direction of feed being of lesser width than the wider of the two ledges parallel to the axis in the direction of loading.

15. In the slide gate of claim 13, - said orifice being centrally located along the intended axis of throttling.

16. In the slide gate of claim 13, - said ledge in the direction of feed being symmetrical about the axis in the direction of feed.

17. In the slide gate of claim 14, - said ledges in the direction of feed being symmetrical about the axis in the direction of feed.

18. In the method of claim 10, - forming the rails for feed and the ledges for feed of a lesser width than the wider of the two rails for loading and ledges for loading which are parallel to the direction of loading and throttling.

19. A slide gate for use in a sequential sliding gate valve having asymmetrical means for inserting said gate along a direction of loading, and thereafter having means for insertion in a direction for feeding, and thereafter in a direction of throttling, and useful in a frame of essentially rectangular configuration surrounding and retaining a refractory, comprising:
- a refractory inserted interiorly of and secured to said frame, - said refractory having an orifice, - ledges in asymmetrical configuration underneath the frame and refractory at the edge portions thereof and parallel to the direction of loading, - and ledges in the direction of feeding which are essentially in perpendicular relationship to the asymmetrical loading edges.

20. In the slide gate of claim 19, - said orifice being offset along the intended direction of throttling.

21. In the slide gate of claim 19, - said ledges in the direction of feeding being symmetrical in the direction of feeding.

22. In the slide gate of claim 19, - said ledges in the direction of feeding being symmetrical in the direction of feeding.

23. In a full throttle tundish valve having a plurality of yieldable means for engaging the downstream side of a plate portion of a submerged pour tube holder to apply sealing force to the submerged pour tube holder, a sliding gate, a stationary plate, a loading portion, and a feeding portion, said feeding portion including a teeming and throttling portion perpendicular with the loading portion, the improvement comprising, - opposed rails in the loading portion of said tundish valve for engaging and loading a slide gate, - said rails in the loading portion of said tundish valve for engaging and loading a slide gate, - said rails being asymmetrical when viewed from the direction of loading the slide gate to thereby accommodate a slide plate which has asymmetrical undercut ledges in the direction of loading, - and means for blocking off one end of the lefthand/righthand loading of said tundish valve, whereby the asymmetrical loading rails insure that a slide plate having an orifice only be loaded into the valve in one configuration of the relationship of the orifice to the loading portion of the valve.

24. A method of preventing reversibility of a slide gate in a sequential valve having a loading direction and a feeding direction essentially perpendicular to the loading direction, comprising the steps of, - forming asymmetrical ledges in parallel relationship to the underneath portion of slide plate in a direction of loading, - securing loading rails in the valve to conform to the offset ledges in the slide plate in the direction of desired loading, - engaging means for closing the loading portions of a valve opposite the portion in which loading is desired, - and securing rails for engaging the opposite underneath portions of the slide gate in perpendicular relationship to the rails of the feed.

25. In the method of claim 24 above, - offsetting the orifice in said slide plate along the direction of loading and throttling.

26. In the method of claim 24 above, - fixing the rails for feed and the ledges for feed perpendicular to the direction of throttling in symmetrical relationship.

27 . A refractory slide gate for use in a sequential sliding gate valve having asymmetrical means for inserting said gate along a direction of loading and thereafter having means for inserting along a direction of feeding, and thereby a direction of throttling comprising, in combination, - a frame of essentially rectangular configuration surrounding and retaining a refractory, - said refractory slide gate having an orifice, - ledges of unequal width on opposing edge portions below the top surface of the slide gate parallel to the direction of loading, - and ledges of equal or near equal width on opposing edge portions below the top surface of the slide gate parallel to the direction of feeding which is essentially perpendicular to the axis in the direction of loading.

28. In the slide gate of claim 27, - said ledges parallel to the axis in the direction of feed being of lesser width than the wider of the two ledges parallel to the axis in the direction of loading.

29. In the slide gate of claim 27, - said orifice being centrally located along the intended axis of throttling.

30. In the slide gate of claim 27, - said ledge in the direction of feed being symmetrical about the axis in the direction of feeding.

31. In the slide gate of claim 28, - said ledges in the direction of feed being symmetrical about an axis in the direction of feeding.

32. In the method of claim 24, - forming the rails for feed and the ledges for feed of a lesser width than the wider of the two rails for loading and ledges for loading which are parallel to the direction of loading and throttling.

33. A slide gate for use in a sequential sliding gate valve having asymmetrical means for insertinq said gate along a direction of loading and thereafter having means for inserting in a direction of feeding, and thereby a direction of throttling comprising, in combination, - a frame of essentially rectangular configuration surrounding and retaining a refractory, - a refractory inserted interiorly of and secured to said frame, - said refractory having an orifice, - ledges having differing cross-sectional configuration underneath the frame and refractory at the edge portions thereof and parallel to the direction of loading, - and ledges in the direction of feeding which are essentially in perpendicular relationship to the loading ledges of differing cross-section.

34. In the slide gate of claim 33, - said orifices being offset along the intended axis of throttling.

35. In the slide gate of claim 33, - said ledges in the direction of feed being symmetrical in the direction of feed.

36. In the slide gate of claim 34, - said ledges in the direction of feed being symmetrical in the direction of feed.

37. In a full throttle tundish valve having a plurality of yieldable means for engaging the downstream side of a plate portion of a submerged pour tube holder to apply sealing force to the submerged pour tube holder, a slide gate, and a stationary top plate, a loading portion, a teeming and throttling portion perpendicular with the loading portion, the improvement comprising, - opposed rails in the loading portion of said tundish valve for engaging and loading a slide gate, - said rails being asymmetrical and of differing cross-section when viewed from the direction of loading the slide gate to thereby accommodate a slide plate which has undercut edges of different cross-section in the direction of loading, whereby the asymmetrical loading rails insure that a slide plate having an orifice only be loaded into the valve in one configuration of the relationship of the orifice to the loading portion of the valve.

38. A method of preventing reversibility of a slide gate in a valve having a frame, means for loading a slide gate, and means for feeding a slide gate respectively in a direction of loading and feeding, comprising the steps of, - forming ledges of differing cross-section in parallel relationship to the underneath portion of a slide plate in the direction of loading, - forming the loading rails in the valve to conform to the ledges of differing cross-section in the slide plate in the direction of desired loading, - actuating means for closing the loading portions of a valve opposite the portion in which loading is desired, - and forming rails for engaging the opposite underneath portions of the slide gate in perpendicular relationship to the rails of feed.

39. In the method of claim 38 above, - offsetting the orifice in said slide plate along the direction of loading and throttling.

40. In the method of claim 33 above, - forming the rails for feed and the ledges for feed perpendicular to the direction of throttling symmetrical relationship.

41. A slide gate for use in a sequential sliding gate valve having asymmetrical means for inserting said gate along a direction of loading and thereafter means for guiding said gate in a direction of feeding, and thereafter a direction of throttling comprising, in combination, - a frame of essentially rectangular configuration surrounding and retaining a refractory, - a refractory inserted interiorly of and secured to said frame, - said refractory having an orifice, - ledges of unequal dimension on opposing edge portions below the top surface of the slide gate parallel to an axis in the direction of loading, - and ledges of functionally equal width on opposing edge portions below the top surface of the slide gate parallel to an axis in the direction of feed which is essentially perpendicular to the axis in the direction of loading.

42. In the slide gate of claim 41, - said ledges parallel to the axis in the direction of feed being of lesser dimension than the greater of the two ledges parallel to the axis in the direction of loading.

43. In the slide gate of claim 41, - said orifice being centrally located along the intended axis of throttling.

44. In the slide gate of claim 41, - said ledge in the direction of feed being symmetrical about the axis in the direction of feed.

45. In the slide gate of claim 42, - said ledges in the direction of feed being symmetrical about the axis in the direction of feed.

46. In the method of claim 33, - forming the rails for feed and the wedges for feed of a lesser dimension than the greater of the two rails for loading and ledges for loading which are parallel to the direction of loading and throttling.