NZ200472A - Valve for controlling teeming from vessel outlet - Google Patents

Description

<div class="application article clearfix" id="description"> <p class="printTableText" lang="en">9) A <br><br> -&lt;&lt;• \J ^ <br><br> Priority Date{s): <br><br> Complete Specification Filed: 3.c?7.Lt7?P* Class: Ztth'M ;....EibK^J ?.?? ;4 k8 AW19851 ;Publication Dste: '. ;P.O. Journal, No: J.?.?.?.... ;NEW ZEALAND PATENTS ACT, 1953 PATENT ;No: 30 APR 198 ;Date: ftECBV£&lt; ;COMPLETE SPECIFICATION ;"VALVE SUITABLE FOR CONTROLLING TEEMING FROM FURNACE ;TAPHOLES" ;k/We, USS ENGINEERS AND CONSULTANTS, INC. , a corporation organized and existing under the laws of the State of Delaware, United States of America, doing business at 600 Grant Street, Pittsburgh, State of Pennsylvania, United States of America, ;hereby declare the invention for which If / we pray that a patent may be granted toxsa/us, and the method by which it is to be performed, to be particularly described in and by the following statement: - ;- 1 - ;20047 ;VALVE SUITABLE FOR CONTROLLING TEEMING FROM FURNACE TAPHOLES ;The present invention relates to a valve suitable for controlling teeming from a vessel outlet 5 such as a furnace taphole. ;When an arc furnace is tapped conventionally, molten metal and slag flow over the furnace pouring lip as the furnace is tilted. The metal and slag then run down a trough, where such is provided, and gather in a 10 ladle. The presence of slag is a considerable inconvenience. Thus, it would be advantageous to be able to empty the furnace of its molten metal and to leave the slag behind. ;By providing the furnace with a taphole located 15 well below the top thereof, it is possible to pour off the molten metal alone when the furnace is tilted. Some form of stopper is needed to close the taphole until pouring is to take place. Better still would be a valve openable and closable at will, for this would facilitate ;200472 ;- 3 - ;the filling of several ladles from one furnace charge, and the furnace would only need tilting once, at the start of the emptying operation. ;In principle a sliding gate valve might appear 5 suitable for controlling flow out of the taphole. ;However, no known sliding gate valve is suitable. The known valve mechanism occupy considerable space to either side thereof i.e. along the direction of movement of the sliding valve plate. Adequate space is absent in 10 the region of a furnace taphole, however, in part due to the presence of the pouring trough. ;An object of the present invention has been to adapt the sliding gate valve concept to suit a furnace taphole arrangement, and a mechanism has been devised 15 in which the sliding valve plate is biased towards the taphole and is moved to and fro from above the trough. ;According to the present invention, there is provided a valve mechanism for controlling metal flow from a vessel outlet, comprising an orificed stationary 20 valve plate, a companion slidable valve plate for covering or exposing the orifice of the former to close or open the valve to flow, extending obliquely to the slidable plate for an actuating member moving the slidable plate, spring means acting to bias the actuating 25 member against the slidable plate to press the slidable ;- 4 - ;y A 7 ;A'- v 'v j 44 ;plate to the stationary plate, and mean^ guiding the actuating member for displacement along a predetermined path wherein a portion of the actuating member engaging the slidable plate moves in a plane parallel to the 5 contacting faces of the valve plates. ;Although the present valve has been devised particularly with furnaces in mind, it has application to other vessels. Thus, the compact form of the valve and the location, to one side of a vessel teeming opening, 10 of its structure for biassing and for moving the slide plate to and fro may be found of significant convenience for some ladles, tundishes and other vessels from which molten metal is to be teemed. ;The invention will now be described in more 15 detail by way of example with reference to the accompanying drawings, in which: ;Fig. 1 is a front elevation of an arc furnace fitted with a taphole valve mechanism according to the invention; ;20 Fig. 2 is a side elevational view of the equipment shown in Fig. 1; ;Fig. 3 is an enlarged sectional elevation of the valve arrangement and ducting leading thereto from the taphole; and ;200472 ;- 5 - ;Fig. 4 is a diagrammatic geometrical analysis of the valve mechanism. ;Referring first to Fig. 3, a taphole insert 10 is positioned in a furnace taphole, the insert 10 having 5 a flow passage of oval cross-section. Abuttingly sealed to the taphole insert 10 is an intermediate duct 11 having a flow passage which changes from oval to circular cross section. A nozzle piece 12 is cemented into the duct 11 and a valve generally designated 14 is 10 disposed at the end of the nozzle piece 12 remote from the taphole, and is sealed thereto. ;In essence, the valve 14 comprises a stationary apertured valve plate 15 of ring form and a slide plate 16 of disc form biased thereagainst. Clamps 17 (Fig. 1) 15 secure the plate 15 in abutment with nozzle piece 12. ;The slide plate 16 is movable in an upward direction, to uncover the opening 18 in the stationary plate 15 and thus open the tapping channel, by an actuating member 20 which is also arranged to thrust the plate 16 against 20 the plate 15. When the tapping channel is opened by raising the slide plate 16, metal flows from the furnace through the taphole insert 10, the intermediate duct and the stationary plate 15, issuing from the latter into pouring trough 21. Metal flows then down the trough 25 into the receiving vessel or ladle. ;200472 ;6 ;When the slide plate 16 is shifted upwardly to open the valve 14 completely it travels a distance almost equal to its diameter. The width of the ring-shaped plate 15, that is the difference between its inner and outer 5 radii, is substantially smaller than the aforesaid distance. Means is therefore provided to support the slide plate 16 as it is moved upwardly. The said means is a thrust plate 22 mounted adjacent the plate 15.on a frame member 23 of the valve. The thrust plate 22 10 and stationary plate 15 have coplanar slide plate contact surfaces 24, 25. ;15 performs two functions. First, it biases the slide plate 16 against the stationary plate 15, thanks to spring means 41 acting on the actuating member. Secondly, it operates to displace the slide plate 16 when an actuator 26 is suitably energised. The actuator member 20 20 is a beam forming part of a linkage 28 so designed that the lower end of the actuator member moves in a vertical path as the actuator 26 is operated. ;inclined to the vertical, and to frame member 23, and 25 has its lower end coupled1 to the slide plate. The ;The valve mechanism will now be described with particular reference to Figs. 2 and 3. ;The actuating member 20 for the slide plate 16 ;As illustrated, the actuator member 20 is ;200472 ;7 ;coupling comprises a pin 30 which is received in a yoke 31 forming part of a shoe 32 mounted in a recess 33 in the slide plate 16, see Fig. 3. ;At an intermediate point along its length, the actuator member 20 is pivotally secured at 37 to a link 34 fast with a pivot shaft 35 journal led to a second frame member 36 of the mechanism. ;The actuating member 20 extends beyond link 34 and has its upper end 38 coupled to the frame member 23. The spring means, which constitutes a spring link 44, couples the beam to the frame member 23 by way of a rigid lever 39 and toggle arrangement 50, to be described. The spring link 44 is pivotally connected at its opposite ends to the lever 39 and end 38, respectively. ;The spring link 44 is a device comprising a multiplicity of compression springs 41, e.g. ten or twelve, which are threaded on a corresponding plurality of bolts holding a pair of thrust plates 42 together. The thrust plates 42 each have a projecting eye or clevis 43 by which the spring link is secured to lever 39 and the end 38. In the operative condition shown in Fig. 2, the springs 41 installed in the link 44 are in a state of compression the link 44 therefore tends to rotate the activating member 20 anticlockwise about its pivotal connection 37 with link 34. Thus, the lower end of the actuating member 20 is biased towards the taphole, and the slide plate 16 is thrust into firm, sealing contact with the stationary plate 16. ;/ ;200472 ;-8- ;The spring means 25 installed in spring link 44 could include a set of Bellville washers instead of coil springs if desired. ;For displacing the slide plate between its open (raised) and closed (lowered) positions, the actuator 26 is linked via a crank 46 to the linkage 28. The crank 46 is fast at one end with the shaft 35 on which the link 34 is also fast. The actuator 26 is pivoted to the opposite end of the crank 46 and when this end is displaced upwardly, the shaft 35 is rotated clockwise and with it link 34. This action serves to displace the actuator member 20 and the slide plate 16 upwardly, to open the valve. ;As shown in the drawings, the actuator 26 is an hydraulic or pneumatic ram. This has its piston rod 47 pivoted to the crank 46 and its body 48 remote from the piston rod pivoted to a lug 49 on the frame member 23. ;Use of such an actuator is conventional in the sliding gate art, but other actuators could be substituted. For instance, the crank 46 could be actuated by, or even replaced by, an appropriate manual control lever. ;The linkage 28, comprising actuating member 20, link 34 and spring link 44, acts approximately as a parallel motion device. The geometry of link 34 and spring link 44 is such as to constrain the actuating ;200472 ;-9- ;member 20 to move substantially parallel to itself. By this means, the lower end of the actuator moves vertically with the slide plate and changes in thrust which it exerts upon the slide plate 16 are kept within safe bounds as the latter is moved vertically by the actuating member 20. ;The spring link 44 acts as a swing link in the linkage 28. It swings, in the same direction as the link 34, about an anchorage 51 at the free end of lever 39 which is pivoted at 52 to the frame member 23. In normal use, however, the level 39 is rigid being barred from pivoting about the pivot at 52 by the toggle arrangement 50. The expansive effort developed by the springs 41 in the spring link 44 applies a force to rotate lever 39 anticlockwise about 52. Such rotation is prevented, however, by the toggle 50 acting as a rigid brace between the lever 39 and frame member 23, thanks to the toggle bearing against a stop 53. Overcentering of the toggle would be necessary if the lever 39 were to move in the opposite direction about 52, so this movement is resisted and moreover is positively prevented by a removable safety pin 54. In normal usage the parts retain the configuration shown in Fig. 2, when the anchorage 51 is fixed. ;200472 ;- 10 - ;On occasion, it will be necessary to replace one or both the plates 15, 16. The spring-developed thrust on plate 16 normally exceeds 5 tons, in the valve-closed setting and must be released for servicing. ;5 This is accomplished by collapsing the anchorage^l on lever 39fby manipulation of the toggle 50. First, the safety pin 54 is removed. Then, crowbars 55 are located in bosses 56 at the ends of a rod passing through the centre of the toggle 50, and forming the centre pivot thereof. ;10 Thereafter the crowbars are levered so as to overcentre the toggle 50 and allow the lever 39 to swing anticlockwise about its pivot at 52. This movement is accompanied by relaxation of the spring means: 41 in the link 44, which can then' for convenience be disconnected from the anchorage 51. ;15 Having released the spring biasing in this way, the actuating member 20 can be swung away from the valve allowing clear access thereto. Restoration of the spring biasing is in substance a reverse of the foregoing steps, ;as will be recognised. ;20 In the present embodiment, the linkage 28 only approximates to a parallel motion device. This is since the connections between the actuating member 20, ;■- - ^ ;the links 34 and 44 " • •• ---- - ' do not move in arcs of r ;I ;equal radius about centres through the shaft 35 and 25 anchorage 51. The geometry of the system, that is the ;- 11 - ;200472 ;respective lengths of link, . 34 and spring link 44 coupled with the positions of their swing centres through 35 and 51, act to minimise changes in the oblique attitude of the actuating member 20 as the actuator 26 5 is extended or contracted. As a result, the biasing , thrust acting on the slide plate changes but only within safe limits and is at a maximum when the valve 14 is closed. ;Example ;10 A specific example of the geometry of a tap- ;hole valve system according to this invention is presented in Fig. 4 of the drawings. ;In this example, the valve slide plate has a diameter of the order of 335 mm and a throw, or travel 15 of 320 mm between valve-open and valve-closed settings. ;The spring link 44, which comprises twelve compre-' ssion coil springs 41, is 385 mm long when relaxed !d and 360 mm long when compressed. The load on each spring 41 is 950 lbs (431 kg) and the springs 41 push the thrust plates 20 42apart with an aggregate force of 5 tons (5080 kg). ;With the left hand face A of frame member 2 3 and the centreline B of the pouring passage as datums, the mechanism has the following dimensions: ;- 12 - ;200472 ;The distance between the two piivot axes of link 34 is 632 nun and pivot axis through shaft 35 is centred 600 mm above B and 214 mm to the right of A; ;5 - in the normal operative condition, the pivot axis through the anchorage 51 is centred 1116 mm above B and is 332 mm to the left of A; pivot point 52 of lever 39 is situated 80 mm to the left of A and 1368 mm above B; 10 - the toggle 50 is connected by a pivot pin to a lug 58 fast with the frame member 23; the pin is centred 80 mm to the left of A and 1017 mm above B. The connection between the toggle 50 and the lever 39 is 24 8 mm from pivot 15 point 52, the distance between the latter and the centre of the fixed anchorage being 356 mm. The links of the toggle each have their two pivot apertures 125 mm apart; and the actuator member 20 is 1100 mm long, the 20 link 34 being pivoted thereto at a centre ;580 mm from the centre of the attachment of ;I ;spring link 44 thereto and 520 mm from the pin 30 coupling the actuating member 20 to the slide plate 16; the pin 30 is centred 25 170 mm to the left of A. ;200472 ;13 ;In operation, when the link 34 is swung clockwise or anticlockwise on the shaft 35, the actuating member 20 is displaced substantially parallel to itself, the motion of its lower end being confined to a vertical plane. The pivotal connection between the link 34 and the actuating member moves along arcuate path C, while the pivotal connection between the spring link 44 and the actuator moves along the approximately parallel arcuate path D. ;The force exerted by the springs 41 in the link 44 on the actuating member 20 normal thereto is at a maximum in the valve-closed setting. When the valve is opened, the normal resolved force falls, owing to the swinging motion of the link 44 about anchorage 51 reducing the angle between the link 44 and the longitudinal axis of the actuating member 20. It follows that the force applied in a direction normal to this axis by the actuating member 20 on the slide plate 16 similarly drops as the valve 14 is opened. ;The following tabulation gives the forces applying as the slide plate is raised from its valve closed setting (1) to the limit of its travel (9), through evenly spaced intermediate positions. ;- 14 - ;2004 ;Position ;Force of spring means on actuating member normal thereto ;Forcc normal to actuating member exerted on slide plate ;Thrust on slide plate resolved normal thereto ;Tons kg ;Tons kg ;Tons kg ;9 ;2.59 ;2631 ;2.89 ;2936 ;2.62 ;2662 ;8 ;3.15 ;3200 ;3.51 ;3566 ;3.15 ;32C0 ;7 ;3.60 ;3657 ;4.02 ;4084 ;3.55 ;3607 ;6 ;3.98 ;4043 ;4.44 ;4511 ;3.90 ;3962 ;5 ;4,34 ;4409 ;4.84 ;^917 ;4.25 ;.t&gt; V-N' ;CD ;4 ;4.60 ;4674 ;5.13 ;5212 ;4.50 ;4572 ;3 ;4.74 ;4816 ;5.29 ;5375 ;4.66 ;4735 ;2 ;4.85 ;4928 ;5.41 ;5497 ;4.80 ;4877 ;1 ;4.94 ;5019 ;5.51 ;5598 ;4.95 ;4663 ;In this example, the mechanical advantage of the actuating member 20 is 580/520 of 1.115. ;From the foregoing it will be appreciated that the means for biasing the slide plate 16 into sealed 20 contact with the stationary plate 15 and the means for drawing the slide .plate 16 aside to open the valve 14 are disposed to one side of the mechanism, and to one side of the pouring passage. The valve arrangement commends itself for any situation where space to one 25 side of a pouring passage is limited. Thus, use of the ;* <br><br> 200472 <br><br> - 15 - <br><br> arrangement is not confined to furnace taphole control. <br><br> Various modifications will be apparent to the addressee. For example, the actuator could act otherwise than through lever 46 and shaft 35 for displacing 5 the linkage 28. Thus, as one possibility the actuator could be coupled to the pin 30. In principle, the spring link 44: could act on the actuating member 20 at any point thereon between link 34 and the slide plate 16, the springs 41 therein then functioning in tension. The 10 positions of the link, 34 and the spring link 44 could then be interchanged. <br><br> In the specific embodiment the linkage is so designed that the bottom end of the actuating member 20 travels vertically. In a modification, the linkage 15 28 could be replaced by a vertically-extending guide in which the bottom end of the actuating member 20 moves. <br><br> The furnace/valve arrangement has the valve 14 and its mechanism located between the furnace wall 70 and the trough 21, the valve being connected by suitable 20 ducting to the furnace taphole. Attachment of the valve mechanism to the furnace wall can be accomplished in various ways and no description of the attachment appears warranted here. <br><br></p> </div>

Claims (14)

<div class="application article clearfix printTableText" id="claims"> <p lang="en"> 200472<br><br> 16<br><br> WHAT WE CLAIM IS:<br><br>

1. A valve mechanism for controlling metal flow from a vessel outlet, comprising an orificed stationary valve plate, a companion slidable valve plate for covering or exposing the orifice of the former to close or open the valve to flow, an actuating member for moving the slidable plate pivotally connected at one end thereto and extending obliquely outwardly therefrom, spring means acting on the actuating member to press the slidable valve plate against the stationary valve plate and a parallel motion linkage assembly connecting said actuating member for guiding the displacement thereof along a predetermined path in which the end connected to said slidable valve plate moves in a plane parallel to the contacting faces of the valve plates.<br><br>

2. A mechanism according to claim 1 wherein the actuating member is part of the linkage assembly, the linkage comprising a pair of oscillatingly movable levers each pivotally connected to the actuating member and to a support structure of the mechanism.<br><br>

- 17 -<br><br>

3. A mechanism according to claim 2, wherein one of the levers is a spring strut and constitutes the spring means which biases the actuating member against the slidable plate.<br><br>

5 A mechanism according to claim 3, wherein the spring strut is pivoted to an anchorage which is carried by the support structure and which is braced thereto by a toggle linkage, the latter being operable to release the anchorage and thereby relieve the biasing of 10 the spring strut on the actuating member.<br><br>

5. A mechanism according to claim 4, wherein the anchorage is on a lever pivoted to the support structure but normally barred from pivoting by the toggle linkage.<br><br>

15

6. A mechanism according to any one of claims<br><br>

3 to 5, wherein the spring strut acting on the actuating member is in a state of compression, and is located further from the slidable plate than the other lever of the linkage.<br><br>

20 '

7. A mechanism according to any one of claims<br><br>

2 to 6 , wherein the pair of levers have such lengths, and their pivotal connections with the support structure are so located relative to the plane of the contacting faces of the valve plates, that the oblique attitude of the 25* actuating member is preserved when displaced to open or close the valve.<br><br>

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8. A mechanism according to any one of claims 1 to 7, including an actuator operable for displacing the actuating member.<br><br>

9 . A mechanism according to claim 8, wherein 5 the actuator is an hydraulic or pneumatic ram.<br><br>

1Q.. A mechanism according to claim 8 or claim 9 when dependent on any one of claims 2 to 7, wherein the actuator acts on a crank fast with a shaft on which one of the levers pivotally connected to the actuating 10 member is also fast, said shaft being journalled to the support structure.<br><br>

11. A valve mechanism for controlling metal flow from a furnace taphole, substantially as herein described with reference to and as shown in Figs. 1 to<br><br>

15 3 of the accompanying drawings.<br><br>

12. A valve mechanism for controlling metal flow from a furnace taphole, substantially as herein described with reference to and as shown in Figs. 1 to 3 and 4 of the accompanying drawings.<br><br>

20

13. A furnace having a taphole in its wall, a pouring trough for conveying metal teemed through the taphole to a receiver vessel, and a valve mechanism according to any of the preceding claims located between the taphole and the trough, the actuating member extend-25 ing obliquely and upwardly away from the trough and the<br><br>

200472<br><br>

20 04-tZ<br><br>

spring means and guide means being located on the opposite side of the slidable plate from the pouring trough.<br><br>

14. A furnace as claimed in claim 13 substantially as hereinbefore described with reference to the accompanying drawings.<br><br>

* .i» *<br><br>

- 19 -<br><br>

uss *■<br><br>

By N4s/Their authorised Agent A. J. PARK &amp; SON Per: "TocK<br><br>

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