IMMERSION NOZZLE EXCHANGING APPARATUS AND UPPER NOZZLE

Abstract

An immersion nozzle exchanging apparatus and an upper nozzle capable of preventing damage to a plate of the upper nozzle are provided. An immersion nozzle exchanging apparatus is mounted on a lower portion of a molten steel outlet of a tundish. The immersion nozzle exchanging apparatus includes a support and a flap. The support has a support surface to support a lower surface of a plate of an upper nozzle inserted into the molten steel outlet. The flap is rotatable with respect to the support. The immersion nozzle exchanging apparatus further includes a rotation stopper for the flap. The rotation stopper includes a wedge to abut against the flap by projecting to an upper side of the flap, and a bolt connected to the wedge, and enables adjustment of a projection amount of the wedge by adjusting a fastening amount of the bolt.

Description

FIELD OF THE INVENTION

The present invention relates to an immersion nozzle exchanging apparatus mounted on a lower portion of a molten steel outlet of a tundish, and an upper nozzle fixed to the immersion nozzle exchanging apparatus.

BACKGROUND

In continuous casting, molten steel is conveyed to a mold from a tundish through an upper nozzle inserted into a molten steel outlet of the tundish and an immersion nozzle connected to the upper nozzle.

As disclosed in Patent Document 1, the upper nozzle includes a tubular portion and a plate in some cases. In this upper nozzle, the plate is fixed by a flap of an immersion nozzle exchanging apparatus.

CITATION LIST

Patent Document

• • Patent Document 1: International Publication No. WO01/81028

SUMMARY

Technical Problem

In fixing the upper nozzle to the immersion nozzle exchanging apparatus by the flap, a rotating cam may be used for a fixing device as disclosed in Patent Document 1. In this case, the cam needs to be pushed by a mallet, causing the fixing device pushed by the cam to make contact with the upper nozzle to possibly damage the upper nozzle.

One aspect of the present invention relates to an immersion nozzle exchanging apparatus and an upper nozzle capable of preventing damage to the upper nozzle.

Solution to Problem

The present invention provides an immersion nozzle exchanging apparatus and an upper nozzle as described below.

1. An immersion nozzle exchanging apparatus mounted on a lower portion of a molten steel outlet of a tundish, the apparatus comprising

• • a support and a flap,
  • the support having a support surface to support a lower surface of a plate of an upper nozzle inserted into the molten steel outlet,
  • the flap being rotatable with respect to the support,
  • the apparatus further comprising a rotation stopper for the flap,
  • the rotation stopper including a wedge to abut against the flap by projecting to an upper side of the flap, and a bolt connected to the wedge, and enabling adjustment of a projection amount of the wedge by adjusting a fastening amount of the bolt.

2. The immersion nozzle exchanging apparatus according to the above item 1, in which

• • the flap has a parallel surface to become parallel to the support surface of the support, and an abutting portion to abut against an outer periphery of a tubular portion of the upper nozzle, when the plate of the upper nozzle is sandwiched between the parallel surface of the flap and the support surface of the support.

3. The immersion nozzle exchanging apparatus according to the above item 1 or 2, in which

• • the bolt is screwed with a bolt guide, and a lock for the bolt is attached to the rotation stopper.

4. The immersion nozzle exchanging apparatus according to the above item 3, in which

• • the wedge is inserted through a wedge guide,
  • the bolt guide and the wedge guide are fixed to a frame, and
  • the frame is fixed to a bottom of the tundish.

5. The immersion nozzle exchanging apparatus according to any one of the above items 1 to 4, in which

• • the parallel surface of the flap has a recess or a projection to be fitted with a projection or a recess provided on an upper surface of the plate of the upper nozzle.

6. An upper nozzle fixed to the immersion nozzle exchanging apparatus according to the above item 5, comprising

• • a tubular portion and a plate,
  • an upper surface of the plate having a projection or a recess to be fitted with the recess or the projection provided on the parallel surface of the flap.

Advantageous Effects of Invention

The present invention can prevent damage to the upper nozzle fixed to the immersion nozzle exchanging apparatus.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of an immersion nozzle exchanging apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view (cross-sectional view along a direction A-A in FIG. 1) of main parts of the immersion nozzle exchanging apparatus in FIG. 1 that are attached to a tundish.

FIG. 3 is an exploded perspective view illustrating a support, a flap, and a spring box.

FIG. 4 is an enlarged perspective view of main parts of the immersion nozzle exchanging apparatus.

FIG. 5 is an enlarged perspective view of main parts of the immersion nozzle exchanging apparatus.

FIG. 6 is a perspective view illustrating a relation between the flap and a rotation stopper.

FIG. 7 is a cross-sectional view along a direction B-B in FIG. 6.

FIG. 8 is a cross-sectional view along a direction C-C in FIG. 6.

FIG. 9 is a cross-sectional view along a direction D-D in FIG. 1.

FIG. 10 is a perspective view illustrating the flap, the spring box, and an upper nozzle.

FIG. 11 is a perspective view illustrating a positioning bolt.

FIG. 12 is a perspective view illustrating another embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

FIG. 1 illustrates an immersion nozzle exchanging apparatus according to an embodiment of the present invention. FIG. 2 is a cross-sectional view along a direction A-A in FIG. 1 illustrating main parts of the immersion nozzle exchanging apparatus that are attached to a tundish.

As illustrated in FIG. 2, an immersion nozzle exchanging apparatus 1 is mounted on a lower portion of a molten steel outlet 101 of a tundish 100. To be more specific, a frame 2 of the immersion nozzle exchanging apparatus 1 is fixed to a shell 102 in a bottom of the tundish 100 by a bolt or the like.

The immersion nozzle exchanging apparatus 1 includes a support 3 to support an upper nozzle 200, and a flap 4 to fix the upper nozzle 200 supported by the support 3. The upper nozzle 200 includes a plate 201 and a tubular portion 202. The tubular portion 202 of the upper nozzle 200 is inserted into the molten steel outlet 101 of the tundish 100. Additionally, the plate 201 of the upper nozzle 200 is connected to a plate 301 of an immersion nozzle 300. Molten steel in the tundish 100 is thereby conveyed to a mold through the upper nozzle 200 and the immersion nozzle 300.

The immersion nozzle exchanging apparatus 1 exchanges the immersion nozzle 300 for a new immersion nozzle. To this end, the immersion nozzle exchanging apparatus 1 includes a pair of guide rails 5 and 5 located in parallel so as to face each other. The pair of guide rails 5 and 5 include inlets 51 and 51 into which the new immersion nozzle is inserted in the exchange of the immersion nozzles, outlets 52 and 52 from which the worn immersion nozzle 300 is discharged in the exchange of the immersion nozzles, and intermediate portions 53 and 53 for supporting the immersion nozzle 300 during operation, respectively. The phrase “during operation” used herein means a period of time during which molten steel is being conveyed to the mold from the tundish.

In the present embodiment, the intermediate portions 53 and 53 are formed by a plurality of key-like pressing members 54 to press the immersion nozzle 300 against the upper nozzle 200. That is, the pressing members 54 support a lower surface of the plate 301 of the immersion nozzle 300 during operation as illustrated in FIG. 2. The pressing members 54 also press the immersion nozzle 300 against the upper nozzle 200 by an elastic force of a coil spring 61 as an elastic body housed in a spring box 6.

As illustrated in FIG. 1, the immersion nozzle exchanging apparatus 1 includes a hydraulic cylinder 7 as a driving device for pushing the new immersion nozzle inserted into the inlets 51 and 51 of the pair of guide rails 5 and 5. The hydraulic cylinder 7 can rotate about a rotating shaft 71 disposed near the inlet 51 of one of the pair of guide rails 5 and 5. In inserting the new immersion nozzle into the inlets 51 and 51 of the pair of guide rails 5 and 5, the hydraulic cylinder 7 is rotated about the rotating shaft 71 to move in an arrow direction E from a position in FIG. 1. After inserting the new immersion nozzle into the inlets 51 and 51 of the pair of guide rails 5 and 5, the hydraulic cylinder 7 is returned to the position in FIG. 1. The hydraulic cylinder 7 then pushes the new immersion nozzle. This allows the new immersion nozzle to move to the intermediate portions 53 and 53 from the inlets 51 and 51 while pushing the worn immersion nozzle 300. The worn immersion nozzle 300 thereby moves to the outlets 52 and 52 from the intermediate portions 53 and 53. The worn immersion nozzle 300 is exchanged for the new immersion nozzle in such a manner.

Next, the support 3 and the flap 4 will be described.

In the present embodiment, the support 3 is provided continuously from the spring box 6. The flap 4 is also mounted on an upper portion of the support 3. FIG. 3 is an exploded perspective view illustrating a relation among the support 3, the flap 4, and the spring box 6.

As illustrated in FIGS. 2 and 3, the support 3 has a support surface 31 to support a lower surface of the plate 201 of the upper nozzle 200. The flap 4 is mounted so as to be rotatable with respect to the support 3 via a rotating pin 43. The flap 4 has a parallel surface 41 to become parallel to the support surface 31 of the support 3 when the plate 201 of the upper nozzle 200 is sandwiched between the support surfaces 31 of the support 3 and the parallel surfaces 41 of the flap 4. The flap 4 further includes an abutting portion 42 to abut against the outer periphery of the tubular portion 202 of the upper nozzle 200 when the plate 201 of the upper nozzle 200 is sandwiched as clearly illustrated in FIG. 4. That is, the abutting portion 42 has a shape in conformity with the outer periphery of the tubular portion 202 of the upper nozzle 200. The flap 4 is provided at two positions so as to sandwich the tubular portion 202 of the upper nozzle 200 as illustrated in FIG. 5.

The immersion nozzle exchanging apparatus 1 further includes a rotation stopper 8 to stop the rotation of the flap 4.

FIG. 6 illustrates a relation between the flap 4 and the rotation stopper 8. The frame 2 is not illustrated in FIG. 6. Additionally, FIG. 7 is a cross-sectional view along a direction B-B in FIG. 6, and FIG. 8 is a cross-sectional view along a direction C-C in FIG. 6. Furthermore, FIG. 9 is a cross-sectional view along a direction D-D in FIG. 1.

As understood from FIGS. 4 and 5, the rotation stopper 8 is provided on opposite sides of each of the two flaps 4. Thus, a total of four rotation stoppers 8 are provided. Each rotation stopper 8 includes a wedge 81 to abut against the flap 4 by projecting to the upper side of the flap 4. A distal end of each wedge 81 has an inclined surface 811 inclined upward. Opposite ends of each flap 4 also have inclined surfaces 44 inclined downward so as to match the inclined surfaces 811 of the wedges 81. The distal end of the wedge 81 has the inclined surface 811 and the opposite ends of the flap 4 have the inclined surfaces 44 as described above. This allows the wedge 81 to easily ride over the upper side of the flap 4.

The wedge 81 is inserted through a wedge guide 82 as illustrated in FIGS. 6 and 7. The wedge 81 is also connected to a wedge bolt 83 within the wedge guide 82. The wedge bolt 83 is screwed with a bolt guide 84. Additionally, the wedge guide 82 and the bolt guide 84 are connected and fixed together by two connecting bolts 85 as illustrated in FIGS. 6 and 8.

The wedge guide 82 and the bolt guide 84 are fixed to the frame 2. To be more specific, the wedge guide 82 and the bolt guide 84 are fixed to the frame 2 so as to allow the inclined surface 811 at the distal end of the wedge 81 inserted through the wedge guide 82 to ride over the inclined surface 44 at each of the opposite ends of the flap 4 as illustrated in FIGS. 7 and 8.

The rotation stopper 8 having such a configuration enables adjustment of a projection amount of the wedge 81 by adjusting a fastening amount of the wedge bolt 83 with respect to the bolt guide 84. The wedge 81 is caused to project until the inclined surface 811 at the distal end of the wedge 81 rides over the inclined surface 44 at each of the opposite ends of the flap 4. The rotation of the flap 4 can be thereby stopped.

Although not illustrated in the drawings, a lock for the wedge bolt 83 may be attached to the rotation stopper 8. As the lock for the wedge bolt 83, a known lock such as a nut and a washer including a disc spring and a coil spring can be attached. The attachment of the lock enables prevention of a chronological change in the projection amount of the wedge 81 due to looseness of the wedge bolt 83. That is, the projection amount of the wedge 81 can be prevented from being reduced due to the looseness of the wedge bolt 83 after fastening the wedge bolt 83 to cause the wedge 81 to project to the position where the wedge 81 can stop the rotation of the flap 4. The rotation of the flap 4 can be thereby certainly stopped.

Next, a method for mounting and fixing the upper nozzle 200 to the immersion nozzle exchanging apparatus 1 will be described.

To mount the upper nozzle 200 on the immersion nozzle exchanging apparatus 1, the wedges 81 are retracted to bring the flaps 4 into a rotatable state by operating the wedge bolts 83. The flaps 4 are brought into a raised state as illustrated in FIG. 10. The upper nozzle 200 is then inserted from above. The support surfaces 31 of the supports 3 support the lower surface of the plate 201 of the upper nozzle 200 as illustrated in FIG. 2. After that, positioning bolts 9 illustrated in FIG. 11 are used to perform positioning of the plate 201 of the upper nozzle 200 in a mounting direction X of the immersion nozzle 300. The frame 2, the flaps 4, the rotation stoppers 8, or the like are not illustrated in FIG. 11.

After positioning, the flaps 4 are brought down. The plate 201 of the upper nozzle 200 is thereby sandwiched between the support surfaces 31 of the supports 3 and the parallel surfaces 41 of the flaps 4. At this time, the abutting portions 42 of the flaps 4 abut against the outer periphery of the tubular portion 202 of the nozzle 200. Positioning of the plate 201 of the upper nozzle 200 in a direction Y perpendicular to the mounting direction X of the immersion nozzle 300 is thereby performed. Additionally, the parallel surfaces 41 of the flaps 4 become parallel to the support surfaces 31 of the supports 3 when the plate 201 of the upper nozzle 200 is sandwiched therebetween. Moreover, the parallel surfaces 41 of the flaps 4 and the support surfaces 31 of the supports 3 also become parallel to an upper surface and the lower surface of the plate 201 of the upper nozzle 200 when the plate 201 of the upper nozzle 200 is sandwiched between the parallel surface 41 of the flap 4 and the support surface 31 of the support 3.

After the plate 201 of the upper nozzle 200 is sandwiched as described above, the wedges 81 are caused to project by operating the wedge bolts 83. To be more specific, the wedges 81 are caused to project until the inclined surfaces 811 at the distal ends of the wedges 81 ride over the inclined surfaces 44 at the opposite ends of the flaps 4. The upper nozzle 200 is thereby certainly fixed to the immersion nozzle exchanging apparatus 1.

After fixing the upper nozzle 200, the immersion nozzle exchanging apparatus 1 is mounted on the lower portion of the molten steel outlet 101 of the tundish 100. To be more specific, the tubular portion 202 of the upper nozzle 200 is inserted into the molten steel outlet 101 of the tundish 100. The frame 2 of the immersion nozzle exchanging apparatus 1 is fixed to the shell 102 in the bottom of the tundish 100 by a bolt or the like.

As described above, the immersion nozzle exchanging apparatus 1 according to the present embodiment fixes the plate 201 of the upper nozzle 200 by sandwiching the plate 201 of the upper nozzle 200 between the support surface 31 of the support 3 and the parallel surface 42 of the flap 4 that are parallel to each other. Thus, fixing the plate 201 causes little impact. Damage to the plate 201 of the upper nozzle 200 can be thereby prevented.

Additionally, since the flap 4 includes the abutting portion 42 to abut against the outer periphery of the tubular portion 202 of the upper nozzle 200 when the plate 201 of the upper nozzle 200 is sandwiched between the support surface 31 of the support 3 and the parallel surface 41 of the flap 4, the positioning of the upper nozzle 200 can be performed in fixing the upper nozzle 200. Moreover, the abutting portion 42 is shaped in conformity with the outer periphery of the tubular portion 202 of the upper nozzle 200. Thus, the positioning and fixation of the upper nozzle 200 can be certainly performed.

Additionally, since the flap 4 can rotate with respect to the support 3, the plate 201 of the upper nozzle 200 can be easily sandwiched therebetween. That is, the parallel surface 41 of the flap 4 can be brought into abutment against the upper surface of the plate 201 only by rotating the flap 4. The plate 201 can be thereby sandwiched between the parallel surface 41 of the flap 4 and the support surface 31 of the support 3.

Furthermore, the immersion nozzle exchanging apparatus 1 according to the present embodiment includes the rotation stopper 8 to stop the rotation of the flap 4. Thus, the plate 201 can be certainly maintained in a sandwiched and fixed state. The rotation stopper 8 also enables adjustment of the projection amount of the wedge 81 by adjusting the fastening amount of the wedge bolt 83. Thus, the rotation of the flap 4 can be easily and certainly stopped. That is, Patent Document 1 described above prevents the rotation of the flap by causing a cam to make contact with a clamp slot. In this technique, the cam may unintentionally rotate to release the fixation of the upper nozzle. Additionally, the fixation is conducted by striking with a hammer. This increases the operator's burden. In contrast, in the present embodiment, the flap 4 is pressed by the wedge 81 from above. The wedge 81 is connected to the wedge bolt 83, which is rotated to adjust the projection amount of the wedge 81. Thus, the possibility that the flap 4 unintentionally rotates to release the fixation of the upper nozzle 200 can be reduced. It is also unnecessary to fix the upper nozzle 200 by striking with a hammer or the like. This enhances safety. By attaching the lock for the wedge bolt 83, the possibility to release the fixation of the upper nozzle 200 can be further reduced.

Next, another embodiment of the present invention will be described. FIG. 12 illustrates main parts of an immersion nozzle exchanging apparatus according to another embodiment of the present invention.

In the present embodiment, a projection 45 is provided on the parallel surface 41 of each flap 4, and a recess 203 is provided on the upper surface of the plate 201 of the upper nozzle 200. The projection 45 is provided at two positions on opposite sides of each parallel surface 41. Thus, a total of four projections 45 are provided. The recess 203 is provided at four positions individually corresponding to the four projections 45. The respective projections 45 are fitted with the corresponding recesses 203 when the plate 201 of the upper nozzle 200 is sandwiched between the support surfaces 31 of the support 3 and the parallel surfaces 41 of the flap 4.

Fitting the projections 45 with the recesses 203 when the plate 201 of the upper nozzle 200 is sandwiched as described above allows the positioning of the plate 201 of the upper nozzle 200 to be easily performed. Thus, the positioning bolts 9 illustrated in FIG. 11 can be omitted.

Additionally, fitting the projections 45 with the recesses 203 allows position misalignment between the flap 4 and the plate 201 to hardly occur.

In the present embodiment, the projections 45 are provided on the parallel surface 41 of the flap 4, and the recesses 203 are provided on the upper surface of the plate 201 of the upper nozzle 200. Conversely, the recesses may be provided on the parallel surface 41 of the flap 4, and the projections may be provided on the upper surface of the plate 201 of the upper nozzle 200. When the projections are provided on the upper surface of the plate 201 of the upper nozzle 200, the plate 201, which is normally covered with a metal case, can be provided with the projections by, for example, welding the projections to the metal case.

While the above embodiments have been described by using the example in which the plate 201 of the upper nozzle 200 has a flat surface, the immersion nozzle exchanging apparatus of the present invention can be also used for an example in which the plate 201 is inclined. In this case, the surface of the flap 4 may be designed to be parallel to the plate.

REFERENCE SIGNS LIST

• • 1 IMMERSION NOZZLE EXCHANGING APPARATUS
  • 2 FRAME
  • 3 SUPPORT
  • 31 SUPPORT SURFACE
  • 4 FLAP
  • 41 PARALLEL SURFACE
  • 42 ABUTTING PORTION
  • 43 ROTATING PIN
  • 44 INCLINED SURFACE
  • 45 PROJECTION
  • 5 GUIDE RAIL
  • 51 INLET
  • 52 OUTLET
  • 53 INTERMEDIATE PORTION
  • 54 PRESSING MEMBER
  • 6 SPRING BOX
  • 61 COIL SPRING (ELASTIC BODY)
  • 7 HYDRAULIC CYLINDER (DRIVING DEVICE)
  • 71 ROTATING SHAFT
  • 8 ROTATION STOPPER
  • 81 WEDGE
  • 811 INCLINED SURFACE
  • 82 WEDGE GUIDE
  • 83 WEDGE BOLT
  • 9 POSITIONING BOLT
  • 100 TUNDISH
  • 101 MOLTEN STEEL OUTLET
  • 102 SHELL (BOTTOM OF TUNDISH)
  • 200 UPPER NOZZLE
  • 201 PLATE
  • 202 TUBULAR PORTION
  • 203 RECESS
  • 300 IMMERSION NOZZLE
  • 301 PLATE
  • 302 TUBULAR PORTION

Claims

1. An immersion nozzle exchanging apparatus mounted on a lower portion of a molten steel outlet of a tundish, the apparatus comprising a support and a flap,the support having a support surface to support a lower surface of a plate of an upper nozzle inserted into the molten steel outlet,the flap being rotatable with respect to the support,the apparatus further comprising a rotation stopper for the flap,the rotation stopper including a wedge to abut against the flap by projecting to an upper side of the flap, and a bolt connected to the wedge, and enabling adjustment of a projection amount of the wedge by adjusting a fastening amount of the bolt.

2. The immersion nozzle exchanging apparatus as claimed in claim 1, wherein the flap has a parallel surface to become parallel to the support surface of the support, and an abutting portion to abut against an outer periphery of a tubular portion of the upper nozzle, when the plate of the upper nozzle is sandwiched between the parallel surface of the flap and the support surface of the support.

3. The immersion nozzle exchanging apparatus as claimed in claim 1, wherein the bolt is screwed with a bolt guide, and a lock for the bolt is attached to the rotation stopper.

4. The immersion nozzle exchanging apparatus as claimed in claim 3, wherein the wedge is inserted through a wedge guide,the bolt guide and the wedge guide are fixed to a frame, andthe frame is fixed to a bottom of the tundish.

5. The immersion nozzle exchanging apparatus as claimed in claim 1, wherein the surface of the flap has a recess or a projection to be fitted with a projection or a recess provided on an upper surface of the plate of the upper nozzle.

6. An upper nozzle fixed to the immersion nozzle exchanging apparatus as claimed in claim 5, comprising a tubular portion and a plate,an upper surface of the plate having a projection or a recess to be fitted with the recess or the projection provided on the surface of the flap.