Door-type rotary nozzle

Abstract

 The invention relates to a door type rotary nozzle attached to a bottom discharge opening of a molten metal container such as ladle or tundish. The nozzle comprises a stationary bottom plate brick (4), having a nozzle bore (4a) in register with said discharge opening (2a); a stationary frame (5); an annular door frame (13) displaceably mounted to said stationary frame; a sliding plate brick (16) having another nozzle bore (16a) capable of communicating with said nozzle bore (4a) of said stationary bottom plate brick and an inner frame (14) supported within said door frame and adapted for holding said sliding plate brick in surfacial contact with said stationary bottom plate brick when said doorframe is closed; a plurality of dogs (19) holding the door frame closed by engaging with said stationary frame; resilient means (15) mounted with resiliency between said door frame (13) and said inner frame (14) and means (8) for driving said inner frame (14) in rotation from the outside thereby rotating said sliding plate brick relative to said stationary plate brick while said door frame remains closed.

Description

[0001] This invention relates to a door type rotary nozzle and more particularly to a door type rotary nozzle mounted to the bottom discharge opening of the molten metal container such as ladle or tundish for controlling the amount of molten metal discharge through said discharge opening through adjustment of the opening degree thereof.

[0002] Rotary nozzles are widely used in conjunction with ladle adapted for receiving and transferring the molten steel tapped from the converter or pouring the same into metal molds, or in conjunction with tundish adapted for reeeiving molten metal tapped from the ladle and pouring the metal into molds. Above all, the door type rotary nozzle, wich has enabled the rotary part inclusive of the sliding plate brick to be opened and closed through attachment by a hinge, has come into widespread use because of a number of advantages proper thereto such that the slidind surface can be exposed for inspection with naked eyes on the state of the plate surface of the stationary bottom plate brick or the sliding plate brick once the valve is opened, an that there is no need to have spare sets in store when the brick is exchanged or repaired, thus facilitating the exchange operation.

[0003] In the door type rotary nozzle, a door frame inclusive of a sliding plate brick is pivotably mounted by a hinge to stationary frame which is secured, either directly or through the medium of a mounting member, to the bottom molten metal discharge opening of the ladle or tundish (hereafter referred to as molten steel ladle). The opening degree of the nozzle is adjusted by transmitting the rotary power from the driving source such as motor through a speed reducing gear and/or counter gear to the sliding plate brick arranged in the door frame, that is by rotating the sliding plate brick.

[0004] Resilient means are provided within the door frame for pressing the sliding plate brick to the stationary bottom plate brick for preventing an accident such as leakage of molten metal due for example to the penetration of molten metal from the bore edge portion into the sliding surfaces of the sliding and stationary bottom plate bricks. The force of reaction of these resilient means is supported by the stationary frame through the door frame and the hinge. When the door frame is opened for repair or exchange as mentioned above, the force of these resilient means render it difficult to disengage the dogs locking the door frame to the stationary frame. As a result thereof, when the door frame is opened, these resilient means need be forcedly compressed in advance from the bottom of the door frame as by jack for disengaging the dogs. Moreover, when the door frame is opened by a hinge with the dogs disengaged, the sliding plate brick released from the compression by these resilient means is apt to be dislodged from within the door frame, with the resulting danger. Hence, these resilient means need be retained or compressed by some or other means.

[0005] The present invention provides an improved door type rotary nozzle in which retention and compression of the resilient means may be effected simultaneously. It is a principal object of the present invention to provide for safe, reliable and simplified opening or closing operation of the door frame, and also to enable the opening or closing operation to be effected through the use of the commonplace jack to the exclusion of the complicated additional structure.

[0006] The door type rotary nozzle of the present invention is comprised of a stationary bottom plate brick having a nozzle bore in register with a molten metal discharge opening at the bottom of a molten metal container such as ladle or tundish; a stationary frame mounted to the bottom of said container for attaching said stationary bottom plate brick to a portion of said discharge opening, an annular door frame displaceably mounted to said stationary frame; hinge means for pivotably connecting said door frame with said stationary frame; a sliding plate brick having another nozzle bore capable of communicating with said nozzle bore of said stationary bottom plate brick when the sliding plate brick is in surfacial contact with said stationary bottom plate brick; an inner frame supported within said door frame and adapted for holding said sliding plate brick in surfacial contact with said stationary bottom plate brick when said door frame is closed, said inner frame being adapted to permit a molten metal discharging collector nozzle to be removably attached thereto within the annular inner periphery of said door frame so that the collector nozzle is in communication with the nozzle bore in said sliding plate brick; a plurality of dogs pivotably mounted to the outer periphery of said door frame and holding the door frame closed by engaging with said stationary frame; resilient means mounted with resiliency between said door frame and said inner frame and adapted for pressing towards said stationary plate brick said sliding plate brick which is in surfacial contact with said stationary bottom plate when said door frame is closed, in such a manner that the resulting force of spring reaction is supported by said stationary frame through said dogs kept engaged with said stationary frame; lug pairs securely mounted to said door frame and said inner frame within the annular inner periphery of said door frame in opposition to each other and being subjected to an exterior force acting for compressing said resilient means when said door frame is opened; and a drive mechanism adapted for driving said inner frame in rotation from the outside thereby causing said sliding plate brick to rotate relative to said stationary plate brick while said door frame remains closed. When opening the door frame, it is required that the dogs be released from the force of reaction of the resilient means supported by the. stationary frame through said dogs. To this end, the lug pairs are clamped together by a jack or the like means for forcedly compressing the resilient means. The jack or the like may remain in the clamping state for maintaining the integrity of the door and inner frames thereby preventing separation thereof from each other.

[0007] According to one embodiment of the invention, a plurality of lug pairs are mounted symmetrically to one another to the annular inner wall region of said door frame for facing to the axis of rotation of said inner frame. According to another embodiment of the invention, the drive mechanism includes an externally threaded annular gear rotor rotatably supported at the outer periphery of said stationary frame, said dogs are engaged with said rotor and said dogs are adapted for being rotated integrally by said rotor together with said inner frame and said sliding plate brick.

[0008] Referring to the drawings :

- Fig. 1 is a bottom view showing a door-type rotary nozzle according to the present invention;

- Fig. 2 is a longitudinal section taken along line II - II of Fig. 1 and looking in the direction of the arrow mark therein;

- Fig. 3 is a perspective view showing the operating state of the essential parts;

- Fig. 4 is a perspective view showing the door-type rotary nozzle of the present invention with the molten metal container inverted and the door open; in these Figures, the same parts are designated by the same numerals.

[0009] Referring to the drawings, the molten metal outlet at the bottom of a molten metal container (1), such as ladle or tundish is generally equipped with an upper nozzle (2) made of a molded article of refractory material. The door-type rotary nozzle of the present invention is provided for controlling the opening or closure of the moltenmetal flowing from the upper nozzle (2). Numeral (3) designates a base member for fixedly supporting the rotary nozzle of the present invention. On the base (3) is secured a stationary frame (5) adapted for holding a stationary bottom plate brick (4) in communication with the upper nozzle (2). The bottom plate brick (4) in the stationary frame (5) has a nozzle bore (4a) in register with a nozzle opening (2a) of the upper nozzle(2) in the assembled state and is replaceably secured within the stationary frame (5) by retainer (6) or screws, not shown. An externally thereaded outergear rotor (8) is provided to the outer periphery of the stationary frame (5) through the intermediary of bearing (7) and driven in rotation by driving means, not shown. An annular member (9) is integrally connected with gear rotor (8) and has on its outer periphery a flange (10) for engagement by six dogs (19) at six peripheral positions and on its inner periphery projections for direct transmission of the rotary power, to an inner frame (14) to be later described, with a hinge (12) being mounted to one end of the periphery of the annular member (9).

[0010] A hinge (12) carries the annular door frame (13) for opening or closure with respect to the annular member (9) of the stationary frame (5). The inner frame (14) is supported in the door frame (13) by springs (¹5). Numeral (16) designates a sliding plate brick replaceably secured to the inner frame (14) by retainer (17) or screws (18) and has two separate nozzle bores (16a), (16b) that may be brought into or out of communication with nozzle bore (4a) of the stationary bottom plate brick (4) when the sliding plate brick is in surfacial contact with the stationary bottom plate brick (4). The inner frame (14) operates in such a manner that, when the door frame (13) is closed with respect to the annular member (9) of the stationary frame (5), the sliding plate brick (16) is brought into surfacial contact with the stationary bottom plate brick (4), the brick (16) being pressed by the spring force of the springs (15) against the stationary bottom plate brick (4) for realizing a sufficient surfacial contact pressure of the said surfacial contact lest the metal penetration should take place. It is dogs (19) provided to six places on the outer periphery of the door frame (13) that support the force of reaction exerted by these springs (15) and holds the door frame (13) in the closed state. These dogs (19) are pivotably mounted to the door frame (13) and the foremost parts thereof are engaged by the flange (10) provided to the outer periphery of the annular member (9) of the stationary frame (5). A hand grip (20) is provided to the tail part of the dog (19) for engaging or disengaging the dogs. The springs (15) are mounted in an annular peripheral chamber (21) of the door frame (13) for resiliently acting between the door frame (13) and the inner frame (14). These springs (15) are coil springsand guide- stopper members (22) are disposed in the inner zone of the springs as shown in Fig. 2 for guiding and preventing excessive flexure caused to the springs (15).

[0011] In register with nozzle bores (16a), (16b) in the sliding plate brick (16), two collector nozzles (23a), (23b) are adapted to be attached at the side of the lower surface of the inner frame (14) in communication with nozzle bores (16a), (16b). In the drawing, (24a), (24b) designate bayonet type mounting cases adapted therefor and (25a), (25b) bayonet type holding socket integrally mounted with the inner frame (14).

[0012] As shown clearly in Fig. 1, two pairs of lugs (26), (27) are provided to the annular inner periphery of the door frame (13) at symmetrical angular positions offset 90 degrees from the collector nozzles (23a), (23b). As shown in Figs. 2 or 3 with respect to one such lug pair (26), each lug pair consists of a pair of lugs (26a), (26b) superimposed one upon the other with a gap (G) therebetween. One lug (26a) projects integrally from door frame (13) and the other lug (26b) projects integrally from the inner frame (14). The gap (G) is larger than the gap (g) between the upper surface of door frame (13) and the lower surface of inner frame (14) or than the gap (ga) between the stoppers (22) and, when the lugs are forced to draw near to each other against the force of springs (15) by the operation of a hydraulic jack (30) and a U-bolt base (31) as shown in Fig. 3 for compressing the springs (15) the door frame (13) approaches to the annular member (9) of the stationary frame (5) to the extent that the dogs (19) can be lightly disengaged by hand. The other lug pair (27) is constructed similarly to the lug pair (26) described above. Jack operation is effected at two positions symmetrical with respect to the center of rotation (28) for balanced compression of the peripherally distributed springs (15) while simultaneously the jack and the base are operated for maintaining the compressed state so that the door frame (13) are not disengaged from the inner frame (14) even when the dogs (19) are disengaged and the door is opened by hinge (12).

[0013] It should be noted that the inner frame (14) has a recess (29) matching with a projection (11) on the inner periphery of the annular member (9) when the door frame is closed and that, when the gear rotor (8) is rotated by a driving gear, not shown, with the door frame (13) closed and the dogs (19) engaged, the force of rotation is transmitted from the annular member (99) to the inner frame (14) through projection (11) and recess (29) and thus the inner frame (14) and hence the sliding plate brick (16) are rotated relative to the stationary frame (5) and hence with respect to the stationary bottom plate brick (4) with door frame (13) being engaged by dogs (19) and without generating inner stress in the remaining portions, the opening degree of communication between the nozzle bores (4a), (16a) being adjusted in this manner from full closure to full opening.

[0014] According to the door type rotary nozzle of the present invention, lug pairs are provided to the inner periphery of the annular door frame (13) between collector nozzles and adapted to be drawn forcedly towards each other by a small sized jack for compressing the springs (15). In this manner, the door frame and the inner frame may be maintained under compression without providing cumbersome protruding parts around the rotating parts that may interfere with rotation thereof thus greatly contributing to the safety in the repair or replacement of bricks and improved operating efficiency. Moreover, a larger force is not required in engaging or disengaging the dogs, the grip need not be of sturdy construction but a grip of reduced length is sufficient thus dispensing with useless protruding portions.

[0015] In the foregoing embodiment, pressure is applied to the lug pair by hydraulic jack (30) and the U-bolt base (31). However, it should be noted that the hydraulic jack may be replaced by screw jack.

Claims

1 - A door type rotary nozzle attached to a bottom discharge opening of a molten metal container such as ladle or tundish, characterized in that it comprises a stationary bottom plate brick (4), having a nozzle bore (4a) in register with said discharge opening (2a); a stationary frame (5) mounted to the bottom of said container for attaching said stationary bottom plate brick to a portion of said discharge opening; an annular door frame (13) displaceably mounted to said stationary frame; hinge means (12) for pivotably connecting said door frame with said stationary frame; a sliding plate brick (16) having another nozzle bore (16a, 16b) capable of communicating with said nozzle bore (4a) of said stationary bottom plate brick when the sliding plate brick is in surfacial contact with said stationary bottom plate brick; an inner frame (14) supported within said door frame and adapted for holding said sliding plate brick in surfacial contact with said stationary bottom plate brick when said door frame is closed, said inner frame being adapted to permit a molten metal discharging collector nozzle to be removably attached thereto within the annular inner periphery of said door frame so that the collector nozzle is in communication with the nozzle bore in said sliding plate brick; a plurality of dogs (19) pivotably mounted to the outer periphery of said door frame (13) and holding the door frame closed by engaging with said stationary frame; resilient means (15) mounted with resiliency between said door frame (13) and said inner frame (14) and adapted for pressing towards said stationary plate brick (5) said sliding plate brick (16) which is in surfacial contact with said stationary bottom plate when said door frame is closed, in such a manner that the resulting force of spring reaction is supported by said stationary frame through said dogs kept engaged with said stationary frame; lug pairs (26, 27) securely mounted to said door frame and said inner frame within the annular inner periphery of said door frame in opposition to each other and being subjected to an exterior force acting for compressing said resilient means when said door frame is opened; and means (8) for driving said inner frame (14) in rotation from the outside thereby rotating said sliding plate brick relative to said stationary plate brick while said door frame remains closed.

2 - The door type rotary nozzle as recited in claim 1, characterized in that a plurality of said lug pairs are mounted symmetrically to one another to the annular inner wall region of said door frame for facing to the center of rotation of said inner frame.

3 - The door type rotary nozzle as recited in claim 1, characterized in that said means for driving said inner frame include an externally threaded annular gear rotor (8) rotatably supported at the outer periphery of said stationary frame (5), said dogs (19) being engaged with said rotor and said dogs and the door frame (13) being adapted for being rotated integrally by said rotor together with said inner frame (14) and said sliding plate brick (16).

Drawing