JP6222119B2 - Snout ash accumulation control device - Google Patents

Description

  The present invention relates to an in-snout ash deposition suppressing device that suppresses ash accumulation in a snout provided between a continuous annealing furnace and a molten metal plating bath in a continuous molten metal plating facility.

  In the continuous molten metal plating method in which a steel strip that has been heat-treated in a continuous annealing furnace is immersed in a molten metal plating bath and the metal strip is continuously plated on the surface of the drawn steel strip, the steel strip is annealed in a reducing atmosphere, so annealing is performed. A mixed gas of nitrogen and hydrogen is blown into the furnace as an atmospheric gas.

  Moreover, in order to suppress oxidation of the steel strip by the external air, a snout having a rectangular cross section is disposed between the annealing furnace and the plating bath. By shutting off the external air and the atmosphere gas in the furnace, the surface of the steel strip is plated with a metal plating bath without oxidation and the plated steel strip is sent to a subsequent process.

  Since the lower part of the snout is immersed in the plating bath surface, molten metal vapor is generated in the snout, and this vapor solidifies and adheres to the relatively low-temperature inner wall of the snout, the previous furnace structure and rolls, etc. accumulate. This coagulum is generally called ash. When the ash falls on the steel strip or the bath surface, it becomes a quality defect such as non-plating and the product yield decreases.

  By the way, in general continuous molten metal plating equipment, in order to discharge foreign matter on the bath surface of the plating bath in the snout, floating metal dross, etc. to the outside of the snout, in the width direction of the steel strip on the bath surface in the snout. A jet pump, a discharge pump, and a dross suction port that form a bath flow are provided. As a result, quality defects can be prevented, but this conventional method has insufficient measures against ash, so that the ash dropped on the bath surface is drawn into the bath and adheres to the steel strip. The product defect may not be resolved. Further, when such a quality defect occurs, it is necessary to stop the production line and clean the inside of the snout, resulting in a problem that productivity is lowered.

  In view of these problems, Patent Document 1 discloses that a suction port is provided at the lower portion of the snout facing the upper surface of the steel strip and an air supply port is provided at the upper portion, and an ejector is provided in the middle of connection by a duct to supply air from the suction port. There has been proposed an ash adhesion suppression method in which an atmospheric gas flow toward the mouth is formed, and metal vapor is solidified by a separator (collecting device) disposed on the upstream side of the ejector. Here, an embodiment of the method proposed in Patent Document 1 is shown in FIG. In the continuous molten metal plating facility 6 of FIG. 3, 61 is a plating bath, S is a steel strip that is continuously pulled up from the plating bath 61, and 614 is disposed on a snout wall surface facing the upper surface of the steel strip at a suction port. A heater 612 is disposed in the vicinity of the suction port. An air supply port 615 is disposed at a position avoiding the steel strip at the top. The suction port 614 and the air supply port 615 are connected by a duct 66, and an ejector 610 that guides atmospheric gas is connected so that a jet flow is generated from the suction port 614 to the air supply port 615, thereby generating an atmospheric gas flow in the snout 62 in the duct. A separator 67b in which the refrigerant 613 circulates is disposed upstream of the ejector 610 so that the metal vapor in the atmospheric gas passing therethrough is solidified. A vibrator 68 is attached to the separator 67b, and an ash is dropped by vibration. A sluice valve 69 and an ash removal cover 611 for taking out the dropped ash to the outside are provided, and ash can be collected during operation.

JP 2005-187855 A

  As described above, according to the method proposed in Patent Document 1, the metal vapor in the snout 62 can be solidified and collected by the separator 67b, and an improvement in productivity can be expected. However, in the method proposed in Patent Document 1, it is necessary to dispose a set of devices such as the duct 66 and the separator 67b in the snout 62, so that the entire device becomes large and equipment costs increase.

  Moreover, according to the method proposed in Patent Document 1, the work becomes complicated due to the ash recovery, which is not preferable. While the ash can be recovered during operation by the gate valve 69 and the ash removal cover 611, there is a safety problem because the ash is recovered on the molten metal bath surface or in the vicinity of the bath.

  Further, according to the method proposed in Patent Document 1, before the metal vapor reaches the separator 67b, the metal vapor is solidified around the suction port 614 or in the duct 66 to block the pipe line, or the ash falls to the steel strip S. Therefore, there is a concern that heating and heat insulation of the in-snout heater 612 and the duct 66 are required as shown in FIG.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an apparatus for suppressing ash accumulation in a snout that can suppress ash accumulation in the snout easily and at low cost.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, it has been found that the above problems can be solved, and the present invention has been completed. More specifically, the present invention provides the following.

  (1) An apparatus for suppressing ash accumulation in a snout disposed in a continuous molten metal plating facility having a dross suction port in the snout, which is provided above the dross suction port in the snout and solidifies by solidifying the metal vapor. A device for suppressing ash accumulation in a snout, comprising: a metal vapor recovery unit that collects as a product, and a drop assisting unit that promotes the fall of the solidified material recovered in the metal vapor recovery unit.

  (2) A gas suction port and a gas exhaust port are formed in a side wall surface of the snout, and further, a duct having one end connected to the gas suction port and the other end connected to the gas exhaust port, and the gas suction And an ejector that sucks the atmospheric gas in the snout from the mouth and exhausts the sucked atmospheric gas from the exhaust port through the duct, the gas suction port of the metal vapor recovery unit in the snout The in-snout ash deposition suppressing device according to (1), wherein the device is present in the vicinity.

  ADVANTAGE OF THE INVENTION According to this invention, the problem by the said ash in a continuous molten metal plating equipment can be suppressed, avoiding a complicated ash collection | recovery operation | work. That is, according to the present invention, the ash collection operation can be performed easily and at low cost. Therefore, according to the present invention, it is possible to produce a high-quality steel strip stably industrially without reducing the productivity, and there is a remarkable industrial effect.

It is a front schematic diagram of the ash accumulation | storage suppression apparatus in a snout arrange | positioned in a snout. It is a side surface schematic diagram of the ash accumulation | storage suppression apparatus in a snout arrange | positioned in a snout. It is a figure which shows typically the conventional ash deposition suppression apparatus in a snout.

  Hereinafter, embodiments of the present invention will be specifically described. In addition, this invention is not limited to the following embodiment.

  FIG. 1 is a schematic front view of an in-snout ash deposition suppressing device arranged in the snout, and FIG. 2 is a schematic side view of the in-snout ash deposition inhibiting device arranged in the snout.

  The in-snout ash deposition suppressing device 1 according to the present invention is disposed below the snout 2 in contact with the plating bath 3. First, a continuous molten metal plating facility (hereinafter sometimes referred to as facility) in which the present invention is arranged will be briefly described.

  1 and 2, a gas suction port 20 and a gas exhaust port 21 are formed in the lower side wall surface. The gas suction port 20 and the gas exhaust port 21 are respectively formed on opposing side wall surfaces so as to sandwich the steel strip S in the width direction of the steel strip S. Further, the gas exhaust port 21 is formed above the gas suction port 20. Moreover, the gas exhaust port 21 is provided in two places on the same side wall surface, and the exhaust from the gas exhaust port 21 flows on both the upper surface and the lower surface of the steel strip S.

  The snout 2 shown in FIGS. 1 and 2 has a bulging portion 22 at the lower portion of the snout. A pair of the bulging portions 22 are formed at both ends of the steel strip S in the width direction. The space in the bulging portion 22 is connected to the space in the main body of the snout 2, and one large closed space is formed in the snout 2.

  A dross suction port 4 exists on the bath surface of the plating bath 3 in the snout 2, and the dross can be discharged out of the snout from the dross suction port 4 through the dross suction pipe 4b by the dross suction pump 4a. (The arrow in the figure represents the flow of dross.)

  In the facility shown in FIG. 1, a jet port 5 is provided in the snout, and the jet pump 5 a connected to the jet port 5 via the jet pipe 5 b extends along the width direction of the steel strip on the bath surface in the snout. A bath stream is formed. The direction of this bath flow is the direction from the jet port 5 toward the dross suction port 4 (see the arrow in the figure).

  Next, the snout ash deposition suppressing apparatus 1 according to the present invention will be described. A snout ash deposition suppressing device 1 according to the present invention includes a metal vapor recovery unit 10, a drop assist unit 11, a duct 12, and an ejector 13.

  The metal vapor recovery unit 10 is provided in the snout 2 above the dross suction port 4. In the facility shown in FIG. 1, a metal vapor recovery unit 10 is provided in one bulge portion 22.

  The metal vapor recovery unit 10 illustrated in FIGS. The metal vapor recovery unit 10 is cooled by the refrigerant 100, and the metal vapor existing in the vicinity of the metal vapor recovery unit 100 is solidified and adhered to the metal vapor recovery unit 10 by this cooling.

  The drop assisting part 11 is for urging the fall of the solidified material recovered by the metal vapor recovery part 10 and is, for example, a vibrator in contact with the metal vapor recovery part 10. If vibration can be directly transmitted to the metal vapor recovery unit 10 such as a vibrator, it is possible to easily promote the fall of the ash that is a solidified product.

  The duct 12 has one end connected to the gas suction port 20 and the other end connected to the gas exhaust port 21 as shown in FIGS. 1 and 2, the snout 2 has two gas exhaust ports 21, and the other end of the duct 12 is branched to connect to the two gas exhaust ports 21. It has become. In the present invention, the number of each of the gas suction port 20 and the gas exhaust port 21 is not particularly limited. However, in the case of a plurality of the gas suction ports 20 and the gas exhaust ports 21, as described above, the ends of the duct 12 are branched and connected to each other. There is a need to.

  The ejector 13 sucks the atmospheric gas in the snout 2 from the gas suction port 20 and exhausts the sucked atmospheric gas from the exhaust port 21 through the duct 12.

  As shown in FIG. 1, since the position of the gas suction port 20 is in the vicinity of the metal vapor recovery unit 10, in the in-snout ash deposition suppressing device 1, the exhaust direction of the atmospheric gas exhausted from the gas exhaust port 21 is the metal The direction is toward the steam recovery unit 10. 1 and 2, there are exhaust toward the metal vapor recovery unit 10 along the upper surface of the steel strip S and exhaust toward the metal vapor recovery unit 10 along the lower surface of the steel strip S.

  Moreover, it is preferable that angle (theta) which the exhaust direction of atmospheric gas exhausted from the gas exhaust port 21 and the horizontal surface which passes the metal vapor recovery part 10 make is 0-60 degrees.

  In the present invention, the duct 12 and the ejector 13 may be omitted.

  Next, the effect of the snout ash deposition suppressing device 1 of the present invention will be described.

  In the in-snout ash deposition suppressing device 1 of the present invention, the metal vapor recovery part 10 is provided above the dross suction port 4, and the solidified substance (ash) solidified and adhered to the metal vapor recovery part 10 is dropped by the drop assisting part 11. Then, the fallen solidified substance is sucked from the dross suction port 4 and is discharged out of the snout 2 through the dross suction pipe 4b by the dross suction pump 4a. By using the dross suction port 4, the ash can be easily discharged out of the snout 2.

  As described above, by providing the metal vapor recovery unit 10 above the dross suction port 4, the fallen solidified material is discharged out of the snout 2 with almost no movement on the plating bath surface in the snout 2.

  As shown in FIGS. 1 and 2, it is preferable that the metal vapor recovery unit 10 is directly above the dross recovery port 4 because the fallen solidified material is immediately sucked into the dross suction port 4. Since a flow toward the dross suction port 4 is generated in the vicinity of the suction port 4, the effect of the present invention can be obtained as long as it is not "directly above" but above.

  As shown in FIGS. 1 and 2, since the snout 2 has the bulging portion 22 at the lower portion, the metal vapor recovery portion 10 can be easily provided in the snout 2.

  If the exhaust direction of the atmospheric gas exhausted from the gas exhaust port 21 is the direction toward the metal vapor recovery unit 10 as in the in-snout ash deposition suppressing device 1 shown in FIGS. Since it goes to the steam recovery unit 10, the discharge of the ash out of the snout 2 can be further promoted, and the problem caused by the ash can be further suppressed.

  1 and 2, the gas suction port 20 and the gas exhaust port 21 are formed on opposing side wall surfaces so as to sandwich the steel strip S in the width direction of the steel strip S, respectively. As a result, a flow of atmospheric gas or metal vapor is generated on the surface of the steel strip S, and problems such as adhesion of ash to the surface of the steel strip S are unlikely to occur. Since the exhaust from the gas exhaust port 21 flows on both the upper surface and the lower surface of the steel strip S, this effect can be further enhanced.

  Moreover, by using the snout 2 having the bulging portion 22, the installation of the in-snout ash deposition suppressing device 1 is facilitated.

  Since the angle θ formed by the exhaust direction of the atmospheric gas exhausted from the gas exhaust port 21 and the horizontal plane passing through the metal vapor recovery unit 10 is 0 to 60 °, the metal vapor is efficiently transferred to the metal vapor recovery unit 10. Can be made.

  The steel strip was hot dip galvanized using the in-snout ash deposition inhibiting device 1 shown in FIGS.

The apparatus of the present invention was used in which the refrigerant was nitrogen gas, the flow rate of the atmospheric gas flowing in the duct was adjusted by an ejector to be 30 Nm ³ / hr, the angle θ was 30 °, the molten zinc temperature was 460 ° C.

  Hot-dip galvanized steel strip products were collected from hot-dip galvanized steel strips, the number of defective products in the collected steel plate products was counted, and the ratio of defective products (number of defective products / number of products x 100 (%)) was calculated. .

  Without using the apparatus of the present invention, the steel strip was subjected to a hot dip galvanizing treatment, and a hot dip galvanized steel sheet product was collected. Then, the defective product ratio was calculated.

  The proportion of defective products when using the apparatus of the present invention was 0.04% lower than when not using the present invention.

DESCRIPTION OF SYMBOLS 1 Snout ash accumulation control device 10 Metal vapor recovery part 11 Drop auxiliary part 12 Duct 13 Ejector 2 Snout 20 Gas suction port 21 Gas exhaust port 22 Swelling part 3 Plating bath 4 Dross suction port 4a Dross suction pump 4b Dross suction pipe 5 Jet 5a Jet pump 5b Jet pipe

Claims (1)

A snout ash deposition suppressing device disposed in a continuous molten metal plating facility having a dross suction port in the snout,
A metal vapor recovery part provided above the dross suction port in the snout, for solidifying the metal vapor and recovering it as a solidified product;
Have a, a falling auxiliary section to promote falling of the recovered coagulum to the metal vapor recovery unit,
A gas suction port and a gas exhaust port are formed on the side wall surface of the snout,
Further, a duct having one end connected to the gas suction port and the other end connected to the gas exhaust port,
An ejector for sucking the atmospheric gas in the snout from the gas suction port, and exhausting the sucked atmospheric gas from the exhaust port through the duct;
The gas suction port is present in the vicinity of the metal vapor recovery part in the snout, and the gas suction port and the gas exhaust port face opposite side walls so as to sandwich the steel strip in the width direction of the steel strip. Each of the snouts has a bulging portion at the lower portion of the snout, and the bulging portions are formed as a pair at both ends in the width direction of the steel strip, and the space in the bulging portion is connected to the space in the snout body. An apparatus for suppressing ash accumulation in a snout , wherein one closed space is formed in the snout, and the metal recovery part is formed in one bulge part of the pair of bulge parts .

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