JP4996343B2 - Lower nozzle holding device and lower nozzle used for it - Google Patents

Description

  The present invention relates to a lower nozzle holding device that joins and holds a lower nozzle to a lower plate constituting a sliding nozzle device for controlling the flow rate of molten metal, and a lower nozzle used in the lower nozzle holding device.

  Since the sliding nozzle device can accurately control the flow rate of the molten metal, it is widely used in various molten metal containers. In this sliding nozzle device, generally two to three plates are used, and the lower nozzle is joined to the lower surface of the lowermost lower plate.

  In general, as shown in FIGS. 6 and 7, the lower nozzle 80 includes a lower nozzle sleeve 74 provided on a lower plate housing metal frame 73 of the sliding nozzle device 72 and a lower portion screwed to the lower nozzle sleeve 74 by a bayonet mechanism. The lower nozzle holding device including the nozzle holder 71 is fastened and fixed. Specifically, a spiral groove 75 is formed on the inner surface of the lower nozzle sleeve 74, and three cotters 76 that are screwed into the spiral groove 75 are formed on the lower nozzle holder 71. When the lower nozzle 80 is mounted, the three cotters 76 of the lower nozzle holder 71 are fitted into the three spiral grooves 75 of the lower nozzle sleeve 74 in a state where the lower nozzle 80 is stored in the lower nozzle holder 71. The lower nozzle holder 71 is screwed to the lower nozzle sleeve 74 by rotating in a predetermined direction. At this time, the handle 77 is struck with a hammer and tightened. Thereby, since the upper end surface of the lower nozzle holder 71 presses the jaw part of the lower nozzle 80, the lower nozzle 80 can be strongly pressed and joined to the lower plate.

  Further, joint materials such as mortar and sealing material are generally filled between the joint surfaces (joint portions) between the lower plate and the lower nozzle to prevent air suction from the gap and leakage of molten metal. However, when used repeatedly, the joint material between the joint surfaces may shrink, or a gap may be generated between the joint surfaces due to expansion and contraction of the surrounding refractory or hardware. Then, air may be sucked from the gap or the molten metal may leak, which is very dangerous. Further, since the contact portion between the lower nozzle sleeve and the lower nozzle holder is lost due to the generation of the gap, the lower nozzle holder may loosen and fall together with the lower nozzle. In order to prevent the occurrence of a gap between the joint surfaces, the lower nozzle holder is generally tightened by hitting it with a hammer once or several times.

  In order to prevent the occurrence of the gap, the applicant of the present application previously described in Patent Document 1 a gap prevention structure between joint surfaces in which an elastic ring is mounted between the jaw portion of the lower nozzle and the tip surface of the lower nozzle holder. Disclosed. Thereby, even if the joint material between the joint surfaces contracts or a gap due to expansion and contraction of the surrounding refractory or hardware occurs, the generation of the gap can be prevented by the urging force of the elastic ring.

  However, in this structure, since the force from the lower nozzle is directly received by the elastic ring, when an external force is applied to the lower nozzle when attaching / detaching the long nozzle, the elastic ring is subjected to a force greater than the repulsive force, There is a possibility that a gap is generated between the joint surfaces. In addition, since the elastic ring has a large diameter, it is liable to be distorted by heat, and the pressing force to the lower nozzle becomes non-uniform, so that there is a problem that the joint surface is easily opened.

  The width of the cotter provided for screwing the lower nozzle holder with the lower nozzle attached to the lower nozzle sleeve is about 30 mm on average, and the outer surface of the lower nozzle holder (outer diameter: about 150 to 250 mm) On the other hand, since the screwing area to the lower nozzle sleeve is very small, there is a problem that the upper surface of the lower nozzle is difficult to be leveled due to poor balance during tightening.

Furthermore, since the lower nozzle holder is strongly struck and tightened with a hammer, each part is easily distorted due to a large force. In particular, the upper end portion that is in contact with the lower nozzle or the cotter screwed to the lower nozzle sleeve is subjected to a greater force and is thus easily deformed greatly. If you continue to use the deformed lower nozzle holder as it is, the adhesiveness of the joint between the lower nozzle and the lower plate will deteriorate and a gap will be generated between the joint surfaces, and air will enter the molten steel from the gap, or There is also a risk of molten steel leaking through the gap.
Japanese Patent Laid-Open No. 10-58124

  A problem to be solved by the present invention is a lower nozzle holding device that can reliably prevent a gap from being generated between joint surfaces (joint portions) between a lower plate and a lower nozzle of a sliding nozzle device, and a lower nozzle holding device that is used in the lower nozzle holding device. The lower nozzle is provided.

The lower nozzle holding device of the present invention is a lower nozzle holding device that holds a lower nozzle joined to a lower plate of a sliding nozzle device, and is attached to a lower plate storage metal frame that holds the lower plate. A cylindrical lower nozzle sleeve having three or more bolt receiving parts on the opposite end, a holder that can be inserted into the lower nozzle sleeve and holds the lower nozzle on the inner surface, and a lower end A cylindrical lower nozzle holder having three or more guides corresponding to the bolt receiving portions on the outer surface of the bolt portion, and three or more bolts inserted into the guides and screwed to the bolt receiving portions. By having the U-shaped groove and rotating the lower nozzle holder around the longitudinal axis, the bolt screwed to the bolt receiving portion can be inserted into the guide from the opening of the U-shaped groove. And kill manner, by tightening the bolt, pushing the bottom nozzle to the lower plate by the holding portion, and is characterized in that the holding and fixing.

  The lower nozzle of the present invention is a lower nozzle used in the lower nozzle holding device of the present invention, and has a large-diameter outer peripheral portion on the upper end side, and a receiving portion at the lower end of the large-diameter outer peripheral portion. When the holding part of the lower nozzle holder is engaged, it is held by the lower nozzle holder, and the ratio L1 / L2 between the outer diameter L1 of the large diameter and the total length L2 of the nozzle is 0.55 or more and 0.85 or less. It is characterized by.

  Since the lower nozzle holding device of the present invention has a structure in which the lower nozzle holder is fixed to the lower nozzle sleeve with a bolt, when the lower nozzle holder is fixed to the lower nozzle sleeve, the lower nozzle holder is hit strongly with a hammer as in the prior art. There is no need to do so, and there is no impact on the lower nozzle holder. Accordingly, the occurrence of distortion of the lower nozzle holder can be suppressed, and the joint surface of the lower nozzle can always be almost parallel to the joint surface of the lower plate. Thickness variation is eliminated.

  In addition, since three or more bolts are used, the thread groove is continuously and densely compared with the screwed structure by the bayonet mechanism, so the parallelism of the joint surface between the lower nozzle and the lower plate is reduced. Increases accuracy and improves sealing performance.

  By these, the lower nozzle holding device of the present invention can surely prevent a gap from occurring between the joint surfaces (joint portions) between the lower plate and the lower nozzle, and air entrainment caused by the occurrence of the gap, etc. The occurrence of trouble can be suppressed.

  Further, as described above, the lower nozzle holding device of the present invention has a structure in which the lower nozzle holder is fixed to the lower nozzle sleeve with a bolt, so that, for example, compared with a case where the lower nozzle holder is directly attached to and detached from the lower plate storage metal frame. There is little influence of heat when attaching and detaching the lower nozzle holder, and safety is high. Furthermore, since the lower nozzle sleeve protrudes downward from the sliding nozzle device, the attaching / detaching operation of the lower nozzle holder and the tightening operation of the bolt can be easily performed, and the workability is also good.

  Further, the guide has a U-shaped groove, and the bolt screwed to the bolt receiving portion can be inserted into the guide from the opening of the U-shaped groove by rotating the lower nozzle holder around the longitudinal axis. Therefore, the operation of inserting the bolt into the guide can be easily performed only by rotating the lower nozzle holder, and the burden of troublesome operations such as temporary pressing and positioning of the lower nozzle holder can be reduced.

  In the lower nozzle of the present invention, the ratio L1 / L2 between the length L1 of the outer periphery of the large diameter and the total length L2 of the nozzle is 0.55 or more and 0.85 or less, so that the lower nozzle is held by the protrusion of the lower nozzle holder. Since the position is set to an appropriate height, it is possible to suppress horizontal shaking caused by joining with the long nozzle and the like, and to improve the adhesion between the lower nozzle and the lower plate. Further, it is possible to suppress the occurrence of horizontal cracks in the lower nozzle or cracks caused by these cracks.

  Embodiments of the present invention will be described below based on examples shown in the drawings.

  1 is a longitudinal sectional view of a lower nozzle holding device according to the present invention, FIG. 2 is a bottom view thereof, and FIG. 3 is a view taken along the line AA in FIG. 4 is a longitudinal sectional view of a lower nozzle holder used in the lower nozzle holding device of FIG. 1, and FIG. 5 is a plan view thereof.

  1 and 2, the lower nozzle holding device 1 is attached to a lower plate housing metal frame 3 of the sliding nozzle device 2. That is, the lower nozzle holding device 1 includes a lower nozzle sleeve 10 attached to the lower plate housing metal frame 3, a lower nozzle holder 20 inserted into the lower nozzle sleeve 10 and holding the lower nozzle 4, and a lower nozzle holder. It consists of a bolt 5 for fixing 20 to the lower nozzle sleeve 10.

  The lower nozzle sleeve 10 is cylindrical and has a flange portion 11 on the lower plate 6 side. The flange portion 11 is fixed to the lower plate housing metal frame 3 with screws (not shown). A lower plate 6 is held on the lower plate storage metal frame 3. Above the inner surface of the lower nozzle sleeve 10 (on the lower plate 6 side), in order to prevent misalignment of the lower nozzle 4, an inner diameter reduced portion 12 having a smaller inner diameter is formed. The inner diameter of the inner diameter reduction part 12 is slightly larger than the outer diameter of the lower nozzle 4 to be used. Specifically, the inner diameter of the inner diameter reduction part 12 is increased in the range of 2 mm or more and 8 mm or less with respect to the outer diameter of the lower nozzle 4. If it is less than 2 mm, it cannot cope with variations in the dimensions of the lower nozzle 4, and if it exceeds 8 mm, misalignment of the lower nozzle 4 tends to occur.

  As shown in FIG. 3, a nut 13 serving as a bolt receiving portion is located at the center of the lower nozzle sleeve 10 on the end of the lower nozzle sleeve 10 opposite to the lower plate 6, that is, on the outer surface of the lower end of the lower nozzle sleeve 10. Four pieces are welded at equal intervals in a concentric manner around the axis. Note that a female screw groove may be provided in the lower end portion of the sleeve main body of the lower nozzle sleeve 10 so as to open the lower end surface, thereby forming a bolt receiving portion.

  The lower nozzle holder 20 has its upper half inside the lower nozzle sleeve 10 with the lower nozzle 4 held inside. At this time, the gap between the lower nozzle holder 20 and the lower nozzle sleeve 10 is in a range of 1 mm to 3 mm on one side to prevent misalignment. The lower nozzle holder 20 has a protrusion 21 protruding in a ring shape on the inner surface as a holding portion for holding the lower nozzle 4 (see FIG. 1).

  As shown in FIGS. 4 and 5, the lower nozzle holder 20 has guides 23 having U-shaped grooves 22 at four locations on the outer surface of the end opposite to the lower plate 6. The four guides 23 are arranged on the same circumference at equal intervals, and the centers of the four U-shaped grooves 22 are the respective screw holes of the four nuts 13 of the lower nozzle sleeve 10. It is arranged so that it can coincide with the central axis. Here, the center of the U-shaped groove 22 is the center of the inscribed circle of the groove in the horizontal section of the groove. The bolt 5 passes through the U-shaped groove 22 and is screwed into a nut 13 provided on the lower nozzle sleeve 10. The U-shaped groove 22 has a slightly larger width than the outer diameter of the bolt 5 so that the direction of the opening is the clockwise direction.

  As shown in FIG. 3, when the lower nozzle holder 20 holding the lower nozzle 4 is attached to the lower nozzle sleeve 10, the upper end surface of the lower nozzle holder 20 and the lower end surface of the inner diameter reducing portion 12 of the lower nozzle sleeve 10 There is a gap between them. If this gap does not exist, that is, if the upper end surface of the lower nozzle sleeve 10 contacts the lower nozzle holder 20, there is a problem in terms of ensuring variation in the length dimension during manufacture of the lower nozzle 4 and additional tightening allowance. For the same reason, a gap is also secured between the upper end surface of the guide 23 and the lower end surface of the lower nozzle sleeve 10. The length of these gaps is preferably 3 mm or more and 50 mm or less. If it is less than 3 mm, it cannot cope with variations in the length of the lower nozzle. If it exceeds 50 mm, the length of the contactable portion between the inner surface of the lower nozzle sleeve 10 and the outer surface of the lower nozzle holder 20 becomes insufficient.

  The bolt 5 is a general bolt having a male screw groove 51 at the tip and a hexagonal head 52 having a large outer diameter on the opposite side.

  As shown in FIG. 1, the lower nozzle 4 has a large-diameter outer peripheral portion 42 on the upper end side, and the protrusion 21 of the lower nozzle holder 20 engages with a receiving portion 41 at the lower end of the large-diameter outer peripheral portion 42 from below. As a result, it is held by the lower nozzle holder, and the upper end surface is joined to the lower plate 6. The lower nozzle 4 has a large-diameter outer peripheral portion 42 having a length L1 = 240 mm, a total length of the nozzle L2 = 350 mm, and L1 / L2 is 0.69. The lower nozzle 4 is connected to a long nozzle or an immersion nozzle on the lower side thereof. These nozzles, which are large, have a length of 1 m or more and vibrate because they receive a force such as a molten steel flow during use. For this reason, the lower nozzle always receives the force from the long nozzle or the immersion nozzle during use. Among these forces, the horizontal force tends to generate a gap at the joint between the lower nozzle 4 and the lower plate 6. As the holding position of the lower nozzle 4 goes upward, the fulcrum is closer to the joint and the force for generating a gap increases. Therefore, particularly when the entire length of the lower nozzle 4 is long, by lowering the holding position of the lower nozzle 4 as much as possible, the influence of the horizontal force received from the long nozzle or the like is reduced, and the generation of a gap at the joint portion is suppressed. be able to. Moreover, the crack of the lower nozzle 4 in the horizontal direction and the crack resulting from this can also be prevented. From the above viewpoint, L1 / L2 is preferably 0.55 or more and 0.85 or less. If it is less than 0.55, the influence by the said vibration will become large, and if it exceeds 0.85, the joining allowance with a long nozzle or an immersion nozzle will be insufficient. This relationship is more preferably applied to a type in which the total length of the lower nozzle is 250 mm or more and 350 mm or less.

  Next, a method for attaching the lower nozzle 4 will be described. Generally, when replacing a refractory, the ladle is tilted 90 degrees to work, so the sliding nozzle device is operated with the axis of the nozzle hole being almost horizontal.

  First, four bolts 5 are screwed into the bolt receiving portion (nut 13) of the lower nozzle sleeve 10 in advance. Next, mortar or the like is applied to the upper end surface of the lower nozzle 4 and pressed against the lower plate 6. At this time, by bringing the lower nozzle 4 into contact with the inner surface of the lower nozzle sleeve 10, the load can be received by the lower nozzle sleeve 10. Moreover, the lower plate side of the inner surface of the lower nozzle sleeve 10 is an inner diameter reducing portion 12, and the gap with the lower nozzle 4 is small. In other words, the inner diameter reduction portion 12 serves as a guide for preventing the deviation of the axial center of the nozzle hole when the lower nozzle 4 is attached.

  After pushing the lower nozzle 4, the lower nozzle holder 20 is inserted into the gap between the lower nozzle 4 and the lower nozzle sleeve 10. Then, the lower nozzle holder 20 is rotated clockwise around the longitudinal axis while being pressed by hand. As a result, each bolt 5 enters into each guide 23 from the opening of the U-shaped groove 22 of each corresponding guide 23, and each bolt 5 is inserted into each guide 23. Thereafter, by tightening each bolt 5, the lower nozzle 4 is joined and held and fixed to the lower plate 6. The tightening position of the lower nozzle 4 can be grasped to some extent by measuring the gap between the guide 23 and the bolt receiving portion (nut 13). Further, the inclination of the lower nozzle 4 can be visually confirmed by this gap.

It is a longitudinal cross-sectional view of the lower nozzle holding | maintenance apparatus of this invention. It is a bottom view of the lower nozzle holding device of FIG. It is an AA arrow line view in FIG. It is a longitudinal cross-sectional view of the lower nozzle holder used for the lower nozzle holding device of FIG. It is a top view of the lower nozzle holder of FIG. It is a longitudinal cross-sectional view which shows the attachment state of the lower nozzle in the conventional sliding nozzle apparatus. It is a disassembled perspective view which shows the attachment point of the lower nozzle in the conventional sliding nozzle apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lower nozzle holding device 2 Sliding nozzle device 3 Lower plate accommodation metal frame 4 Lower nozzle 41 Receiving part 42 Large diameter outer peripheral part 5 Bolt 51 Male thread groove 52 Head 6 Lower plate 10 Lower nozzle sleeve 11 Flange part 12 Inner diameter reduction part 13 Nut 20 Lower nozzle holder 21 Protrusion 22 U-shaped groove 23 Guide

Claims (2)

A lower nozzle holding device that holds and holds a lower nozzle on a lower plate of a sliding nozzle device,
A cylindrical lower nozzle sleeve attached to a lower plate-holding metal frame that holds the lower plate, and having three or more bolt receiving portions at the end opposite to the lower plate;
A cylindrical lower portion that can be inserted into the lower nozzle sleeve, has a holding portion for holding the lower nozzle on the inner surface, and has three or more guides corresponding to the bolt receiving portions on the outer surface of the lower end portion. A nozzle holder,
Including three or more bolts inserted into the guide and screwed into the bolt receiving portion,
Guide has a U-shaped groove, by rotating the lower nozzle holder around the longitudinal axis, a bolt screwed into the bolt receiving portion as can be inserted into the guide from the opening of the U-shaped groove And
A lower nozzle holding device that tightens a bolt and presses and holds the lower nozzle against the lower plate by a holding portion . A lower nozzle used in the lower nozzle holding device according to claim 1 ,
It has a large-diameter outer peripheral portion on the upper end side, and is held by the lower nozzle holder by engaging the holding portion of the lower nozzle holder with the receiving portion at the lower end of this large-diameter outer peripheral portion,
A lower nozzle in which a ratio L1 / L2 between the length L1 of the outer periphery of the large diameter and the total length L2 of the nozzle is 0.55 or more and 0.85 or less.

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