JP6863023B2 - Gas wiping nozzle - Google Patents

Description

The present invention relates to a gas wiping nozzle.

The continuous molten metal plating apparatus is an apparatus for plating a metal strip typified by a steel strip with a molten metal such as zinc. This continuous molten metal plating apparatus includes a sink roll that changes the transport direction of the metal band and a pair of support rolls that flatten the shape of the metal band as rolls arranged in a plating tank that stores the molten metal. .. The metal strip introduced in the plating bath in an oblique direction is pulled up to the outside of the plating bath by passing through while being sandwiched between a pair of support rolls after the transport direction is changed vertically upward by the sink roll. .. After that, gas is blown from the gas wiping nozzles arranged on both sides of the metal band to the surface of the metal band, and the excess molten metal adhering to the surface of the metal band and being pulled up is scraped off, thereby adhering the amount of molten metal. (Hereinafter, also referred to as "grain amount") is adjusted.

At the tip of the gas wiping nozzle, which is the end on the metal band side, a slit extending in the width direction of the metal band is formed as an injection port for gas injected from the inside of the gas wiping nozzle. The gas wiping nozzle injects gas through the slit and sprays the gas onto the surface of the metal band pulled up from the plating bath to remove excess molten metal adhering to the surface of the metal band. Scratch. The slit may be formed, for example, between the tips of a pair of lip portions provided so as to face each other in the vertical direction.

In such a continuous molten metal plating process, the accuracy of the amount of molten metal with respect to the metal band, which is adjusted by gas wiping, depends on the inertial force of the molten metal attached to the metal band and pulled up, and the force of the gas with respect to the metal band. It depends on the balance with the collision pressure. Changes in the slit width of the gas wiping nozzle (hereinafter, also referred to as the slit gap) affect the stability of the gas jet and the gas injection pressure, and can be a factor that changes the collision pressure of the gas with respect to the metal band. .. As a result, the basis weight of the molten metal with respect to the metal band may become unstable. Therefore, various techniques for appropriately adjusting the slit gap of the gas wiping nozzle have been proposed.

For example, Patent Document 1 describes a push rod in which an upper lip portion and a lower lip portion extend through a nozzle body and whose tip abuts on the upper surface of the lower lip portion, and a push rod attached to the outer surface of the nozzle body. A technique for adjusting a slit gap by a gap adjusting mechanism including a rod pushing means for pushing out a rod is disclosed.

Further, in Patent Document 2, at least one of the upper lip portion and the lower lip portion is provided with a hydraulic hole extending along the longitudinal direction of the slit, and the hydraulic hole is provided with a pressurized fluid. Disclosed is a technique for adjusting the slit gap by elastically deforming the lip portion in which the hydraulic pores are formed.

Japanese Unexamined Patent Publication No. 9-2418113 Japanese Unexamined Patent Publication No. 2011-001567

However, with a gas wiping nozzle formed between the tips of a pair of lip portions in which the slits are provided so as to face each other in the vertical direction, a change in the slit gap that is difficult to adjust may occur.

For example, when replacing a part or all of the parts constituting the gas wiping nozzle for maintenance, it may be necessary to reassemble the upper lip portion and the lower lip portion. The slit gap after such assembly can vary from assembly to assembly.

Further, in recent years, in order to improve the productivity in hot metal plating of metal strips such as steel strips, it has been required to increase the transport speed of the metal strips. When the transport speed of the metal strip is increased, the amount of molten metal that adheres to the metal strip and is lifted increases. Therefore, in order to control the basis weight to a desired value, the melt is scraped off by gas wiping. It may be necessary to increase the amount of metal. Here, in order to increase the amount of molten metal scraped by gas wiping, the collision pressure of the gas with respect to the metal band is increased by increasing the gas pressure supplied to the gas wiping nozzle. As a result, the internal pressure of the gas wiping nozzle increases. Due to such an increase in internal pressure, the tips of the upper lip portion and the lower lip portion may be deformed in a direction away from each other. Therefore, the slit gap can be widened.

The larger the change in the slit gap, which is difficult to adjust, the larger the change in the collision pressure of the gas with respect to the metal band. As a result, the basis weight of the molten metal with respect to the metal strip (specifically, the steel strip) may become unstable.

Further, when the internal pressure of the gas wiping nozzle is increased as the transfer speed of the metal band is increased as described above, the gas flow inside the gas wiping nozzle tends to be non-uniform in the width direction of the metal band. Become. As a result, the variation of the collision pressure of the gas with respect to the metal band in the width direction of the metal band may increase. Therefore, the basis weight of the molten metal with respect to the metal strip (specifically, the steel strip) may become unstable.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is a new and improved gas wiping capable of stabilizing the basis weight of molten metal with respect to a steel strip. To provide a nozzle.

In order to solve the above problems, according to a certain viewpoint of the present invention, a film of a molten metal film adhered to the surface of the steel strip by spraying gas onto the steel strip pulled upward from the molten metal plating bath. A gas wiping nozzle for adjusting the thickness, which is provided so as to face each other and is injected from a first lip portion and a second lip portion which form a nozzle chamber into which the gas is introduced, and a nozzle chamber. As the outlet for the gas, a slit formed between the ends of the first lip portion and the second lip portion on the steel strip side and the slit side in the nozzle chamber are provided. The first lip portion and the fixing member fixed to the second lip portion are provided, and the fixing member communicates the slit side and the opposite side of the slit with the fixing member. A plurality of first communication holes are arranged side by side along the width direction of the steel strip, and the gas to be introduced into the nozzle chamber is introduced into the first lip portion and the inside of the second lip portion. gas header chamber Ru is further formed, the gas wiping nozzle is provided.

The first communication holes may be arranged side by side at equal intervals.

Between the front Symbol nozzle chamber and the gas header chamber, a second communicating hole communicating the slit and the opposite side and the gas header chamber in the nozzle chamber is more arranged along the width direction of the steel strip, the The first communication holes may be arranged side by side at shorter intervals as compared with the second communication holes.

A bolt is inserted into the first lip portion and the second lip portion from the outside, and the fixing member is formed by screwing the bolt into the fixing member to form the first lip portion and the fixing member. It is fixed to the second lip portion, and a counterbore hole for accommodating the head of the bolt is formed on the outer peripheral portion of the first lip portion and the second lip portion, and the counterbore hole is closed by a sealing member. May be done.

As described above, according to the present invention, it is possible to stabilize the basis weight of the molten metal with respect to the steel strip.

It is a schematic diagram which shows an example of the schematic structure of the continuous molten metal plating apparatus which concerns on embodiment of this invention. It is a perspective view which shows an example of the gas wiping nozzle which concerns on a reference example. It is an exploded perspective view which shows an example of the gas wiping nozzle which concerns on a reference example. It is sectional drawing which shows an example of the gas wiping nozzle which concerns on a reference example. It is a perspective view which shows an example of the gas wiping nozzle which concerns on the same embodiment. It is an exploded perspective view which shows an example of the gas wiping nozzle which concerns on the same embodiment. It is sectional drawing which shows an example of the gas wiping nozzle which concerns on the same embodiment. It is explanatory drawing which shows the analysis result of the mouth opening amount which is the expansion amount of the slit gap for each of the gas pressures supplied to a nozzle chamber. It is explanatory drawing which shows the analysis result of the collision pressure of a gas with respect to a steel strip at each position in the width direction of a steel strip in a gas wiping nozzle.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification and the drawings, components having substantially the same functional configuration are designated by the same reference numerals, so that duplicate description will be omitted.

<1. Configuration of continuous molten metal plating equipment>
First, the configuration of the continuous molten metal plating apparatus 1 according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic view showing an example of a schematic configuration of a continuous molten metal plating apparatus 1 according to the present embodiment.

As shown in FIG. 1, the continuous molten metal plating apparatus 1 continuously adheres the molten metal to the surface of the steel strip 2 by immersing the steel strip 2 in a plating bath 3 filled with the molten metal. , A device for adjusting the amount of molten metal to a predetermined amount. The continuous molten metal plating apparatus 1 includes a plating tank 4, a snout 5, a sink roll 6, a pair of upper and lower support rolls 7 and 8, and a gas wiping nozzle 10.

The steel strip 2 is an example of a metal strip to be plated with molten metal. Examples of the molten metal constituting the plating bath 3 include simple substances of Zn, Al, Sn, and Pb, or alloys thereof. Alternatively, the molten metal may be added to these metals or alloys, for example, non-metal elements such as Si and P, typical metal elements such as Ca, Mg and Sr, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and the like. It also includes those containing the transition metal element of. In the following description, an example in which hot-dip zinc is used as the molten metal forming the plating bath 3 and hot-dip zinc is adhered to the surface of the steel strip 2 to manufacture a galvanized steel sheet will be described.

The plating tank 4 stores a plating bath 3 made of molten metal. The upper end of the snout 5 is connected to, for example, the outlet side of the annealing furnace, and the lower end is immersed in the plating bath 3 and provided so as to be inclined. The sink roll 6 is arranged below in the plating bath 3. The sink roll 6 has a larger diameter than the support rolls 7 and 8. The sink roll 6 rotates clockwise as shown by the transport of the steel strip 2, and vertically upward in the transport direction of the steel strip 2 introduced obliquely downward into the plating bath 3 through the snout 5. Change to.

The support rolls 7 and 8 are arranged above the sink roll 6 in the plating bath 3, and the steel strip 2 which is changed in direction by the sink roll 6 and is pulled up in the vertical direction is sandwiched from both the left and right sides. The support rolls 7 and 8 suppress the vibration of the steel strip 2 that is pulled up. The support rolls 7 and 8 may be provided only one without pairing, or may be provided in three or more. Alternatively, the arrangement of the support rolls 7 and 8 may be omitted. The top roll 9 is arranged above the plating bath 3 and above the sink roll 6. The top roll 9 is pulled upward from the plating bath 3 in the vertical direction, and the transport direction of the steel strip 2 in which the amount of molten metal is adjusted is changed to the carry-out direction.

The gas wiping nozzle 10 injects a gas such as air sprayed on the surface of the steel strip 2 in order to adjust the basis weight of the molten metal with respect to the steel strip 2. Gas compressed by a compressor or the like (not shown) is introduced into the gas wiping nozzle 10. The gas wiping nozzles 10 are arranged on both sides of the steel strip 2 in the thickness direction, above the support rolls 7 and 8, and at a predetermined height from the bath surface of the plating bath 3. The gas injected from the gas wiping nozzle 10 is sprayed on both sides of the steel strip 2 pulled upward in the vertical direction from the plating bath 3, and excess molten metal is scraped off. As a result, the basis weight of the molten metal with respect to the surface of the steel strip 2 is adjusted to an appropriate amount, and the film thickness of the molten metal film adhering to the surface of the steel strip 2 is adjusted.

Specifically, a nozzle chamber into which gas is introduced is formed inside each of the gas wiping nozzles 10, and a steel strip is formed at the tip of each of the gas wiping nozzles 10 on the steel strip 2 side. A slit extending in the width direction of 2 is formed. The gas introduced into the nozzle chamber is injected from the slit and sprayed onto the steel strip 2. In this way, the slit functions as an injection port for the gas injected from the nozzle chamber.

In the gas wiping nozzle 10 according to the present embodiment, fixing members fixed to a pair of lip portions provided so as to face each other in the vertical direction are provided on the slit side in the nozzle chamber. As a result, it is possible to suppress changes in the slit gap, which is difficult to adjust. Therefore, by stabilizing the collision pressure of the gas with respect to the steel strip 2, the basis weight of the molten metal with respect to the steel strip 2 is stabilized. Is possible. Details of such a gas wiping nozzle 10 will be described later.

The operation of the continuous molten metal plating apparatus 1 having the above configuration will be described. In the continuous molten metal plating apparatus 1, the steel strip 2 is moved by a drive source (not shown), and each part in the apparatus is passed through the plate. The steel strip 2 is introduced obliquely downward into the plating bath 3 through the snout 5, orbits the sink roll 6, and the transport direction is changed upward in the vertical direction. Next, the steel strip 2 passes between the support rolls 7 and 8 and rises, and is pulled out of the plating bath 3. After that, the excess molten metal adhering to the steel strip 2 is scraped off by the pressure of the gas sprayed from the gas wiping nozzle 10, and the amount of molten metal adhering to the surface of the steel strip 2 is adjusted to a predetermined grain amount. Will be done. As described above, the continuous molten metal plating apparatus 1 manufactures a molten metal plated steel sheet having a predetermined grain amount by continuously immersing the steel strip 2 in the plating bath 3 and plating the molten metal. ..

<2. Gas wiping nozzle according to the reference example>
Subsequently, prior to the detailed description of the gas wiping nozzle 10 according to the present embodiment, the gas wiping nozzle 90 according to the reference example will be described with reference to FIGS. 2 to 4. FIG. 2 is a perspective view showing an example of the gas wiping nozzle 90 according to the reference example. FIG. 3 is an exploded perspective view showing an example of the gas wiping nozzle 90 according to the reference example. FIG. 4 is a cross-sectional view showing an example of the gas wiping nozzle 90 according to the reference example. Specifically, FIG. 4 is a cross-sectional view of the AA cross section shown in FIG. The AA cross section is a cross section orthogonal to the longitudinal direction of the slit 940 of the gas wiping nozzle 90. Similar to the gas wiping nozzle 10 according to the present embodiment, the gas wiping nozzles 90 are arranged in pairs on both sides of the steel strip 2 in the thickness direction, but one of them is shown in FIGS. 2 to 4. , The illustration of the other is omitted. Further, in FIGS. 2 and 3, the bolts 951, 952 and the nuts 961 and 962, which will be described later, are not shown. Further, in the following, the steel strip 2 side will be described as the tip side.

As shown in FIGS. 2 to 4, the gas wiping nozzle 90 according to the reference example includes an upper lip portion 910 and a lower lip portion 920 provided so as to face each other in the vertical direction, and the upper lip portion 910 and the lower lip portion 910. It is formed between the shim 930 sandwiched by the lip portion 920 and the tip portion 911 which is the end portion of the upper lip portion 910 on the steel strip 2 side and the tip portion 921 which is the end portion of the lower lip portion 920 on the steel strip 2 side. The slit 940 and the like are included.

As shown in FIG. 4, the upper lip portion 910 and the lower lip portion 920 are provided so as to face each other, and form a nozzle chamber 991 and a gas header chamber 992 inside. The nozzle chamber 991 and the gas header chamber 992 are formed on the front end side and the rear end side of the gas wiping nozzle 90 by the upper lip portion 910 and the lower lip portion 920, respectively, and are provided on the upper lip portion 910 and the lower lip portion 920, respectively. They are communicated with each other by communication holes 913 and 923. Gas is introduced into the gas header chamber 992 from the outside, and the gas is introduced into the nozzle chamber 991 through the communication holes 913 and 923.

Further, the upper lip portion 910 and the lower lip portion 920 are fixed with the shim 930 sandwiched in the vertical direction. The upper lip portion 910, the lower lip portion 920, and the shim 930 are fixed to each other in the vertical direction by, for example, screwing with bolts 951, 952 and nuts 961, 962. Specifically, the upper lip portion 910, the lower lip portion 920, and the shim 930 are fixed by bolts 952 and nuts 962 in the vertical direction at positions on the rear end side of the gas header chamber 992 of the gas wiping nozzle 90. A plurality of pairs of bolts 952 and nuts 962 may be arranged side by side along the width direction of the steel strip 2. Further, the upper lip portion 910, the lower lip portion 920 and the shim 930 are fixed in the vertical direction by bolts 951 and nuts 961 at positions between the nozzle chamber 991 and the gas header chamber 992 in the gas wiping nozzle 90. A plurality of pairs of bolts 951 and nuts 961 may be arranged side by side along the width direction of the steel strip 2. As described above, the upper lip portion 910 and the lower lip portion 920 form a cantilever structure supported on the rear end side.

The shim 930 comes into contact with a portion of each lip portion other than the central side in the width direction of the steel strip 2 at the tip portion. Specifically, the upper portion of the shim 930 comes into contact with a portion of the upper lip portion 910 excluding the central side of the tip portion 911 in the width direction of the steel strip 2. On the other hand, the lower portion of the shim 930 comes into contact with the portion of the lower lip portion 920 excluding the central side of the tip portion 921 of the steel strip 2 in the width direction. Thereby, a gap corresponding to the thickness of the shim 930 can be provided between the tip portion 911 of the upper lip portion 910 and the tip portion 921 of the lower lip portion 920. Therefore, as shown in FIGS. 2 and 4, a slit 940 is formed between the tip portion 911 of the upper lip portion 910 and the tip portion 921 of the lower lip portion 920 as an outlet for the gas injected from the nozzle chamber 991. To. Specifically, the slit 940 extends in the width direction of the steel strip 2.

Further, as shown in FIG. 3, the shim 930 has a pair of lateral extending portions 933 extending from the rear end side to the tip side, respectively, on both end sides in the width direction of the steel strip 2. As a result, the slit 940 is defined in the longitudinal direction by the tips of the pair of lateral extending portions 933.

By the way, when a part or all of the parts constituting the gas wiping nozzle 90 are replaced for maintenance, it may be necessary to reassemble the upper lip portion 910 and the lower lip portion 920. The slit gap after such assembly can vary from assembly to assembly.

Further, when the transport speed of the steel strip 2 is increased, the amount of molten metal adhering to the steel strip 2 and being lifted increases, so that gas wiping is performed in order to control the grain size to a desired value. It may be necessary to increase the amount of molten metal scraped by the nozzle 90. Here, in order to increase the amount of molten metal scraped by the gas wiping nozzle 90, the collision pressure of the gas with respect to the steel strip 2 is increased by increasing the gas pressure supplied to the nozzle chamber 991 of the gas wiping nozzle 90. Is done. As a result, the tips of the upper lip portion 910 and the lower lip portion 920 may be deformed in a direction away from each other due to the increase in the internal pressure of the nozzle chamber 991 of the gas wiping nozzle 90. Therefore, the slit gap can be widened.

Here, in the reference example, as described above, the upper lip portion 910 and the lower lip portion 920 form a cantilever structure supported on the rear end side. Specifically, the upper lip portion 910 and the lower lip portion 920 are fixed on the rear end side of the nozzle chamber 991 of the gas wiping nozzle 90. Therefore, the distance L90 in the thickness direction of the steel strip 2 from the portion where the upper lip portion 910 and the lower lip portion 920 are fixed to each other to the tip portion of the slit 940 is relatively long. As a result, it may be difficult to suppress variations in each assembly of the slit gap after assembly. Further, when the gas pressure supplied to the nozzle chamber 991 of the gas wiping nozzle 90 is increased in order to control the basis weight amount to a desired value while increasing the transport speed of the steel strip 2, the nozzle chamber 991 It can be difficult to prevent the slit gap from widening due to the increase in internal pressure.

As described above, in the reference example, it may be difficult to suppress the change in the slit gap, which is difficult to adjust, so that the change in the collision pressure of the gas with respect to the steel strip 2 can be relatively large. As a result, the basis weight of the molten metal with respect to the steel strip 2 may become unstable.

<3. Gas wiping nozzle according to this embodiment>
Subsequently, the gas wiping nozzle 10 according to the present embodiment will be described with reference to FIGS. 5 to 7. FIG. 5 is a perspective view showing an example of the gas wiping nozzle 10 according to the present embodiment. FIG. 6 is an exploded perspective view showing an example of the gas wiping nozzle 10 according to the present embodiment. FIG. 7 is a cross-sectional view showing an example of the gas wiping nozzle 10 according to the present embodiment. Specifically, FIG. 7 is a cross-sectional view of the BB cross section shown in FIG. The BB cross section is a cross section orthogonal to the longitudinal direction of the slit 140 of the gas wiping nozzle 10. As described above, the gas wiping nozzles 10 are arranged in pairs on both sides of the steel strip 2 in the thickness direction. However, in FIGS. 5 to 7, one of the gas wiping nozzles 10 is illustrated, and the other is omitted. ing. Further, in FIGS. 5 and 6, the bolts 151 and 152 and the nuts 161 and 162, which will be described later, are not shown.

The gas wiping nozzle 10 according to the present embodiment is, for example, as shown in FIGS. 5 to 7, the upper lip portion 110 and the lower lip portion 120 provided so as to face each other in the vertical direction, and the steel strip of the upper lip portion 110. A slit 140 formed between the tip 111 which is the end on the 2 side and the tip 121 which is the end on the steel strip 2 side of the lower lip 120, and the upper lip provided on the slit 140 side in the nozzle chamber 191. It is configured to include a portion 110 and a fixing member 170 fixed to the lower lip portion 120.

As shown in FIG. 7, the upper lip portion 110 and the lower lip portion 120 are provided so as to face each other, and form a nozzle chamber 191 and a gas header chamber 192 inside. The upper lip portion 110 and the lower lip portion 120 correspond to the first lip portion and the second lip portion according to the present invention, respectively.

The nozzle chamber 191 and the gas header chamber 192 are formed on the front end side and the rear end side of the gas wiping nozzle 10 by the upper lip portion 110 and the lower lip portion 120, respectively. Specifically, recesses forming the upper portion of the nozzle chamber 191 and the upper portion of the gas header chamber 192 are formed on the front end side and the rear end side of the lower portion of the upper lip portion 110, respectively. On the other hand, recesses forming the lower portion of the nozzle chamber 191 and the lower portion of the gas header chamber 192 are formed on the front end side and the rear end side of the upper portion of the lower lip portion 120, respectively. The nozzle chamber 191 and the gas header chamber 192 are formed by the upper lip portion 110 and the lower lip portion 120 coming into contact with each other so that the corresponding recesses are connected to each other.

The upper lip portion 110 and the lower lip portion 120 are substantially parallel to each other on the rear end side of the gas wiping nozzle 10, for example, as shown in FIG. Therefore, the vertical dimension of the gas header chamber 192 is substantially constant from the rear end side to the front end side. On the other hand, the upper lip portion 110 and the lower lip portion 120 approach each other on the tip side of the gas wiping nozzle 10 toward the tip side. Therefore, the vertical dimension of the nozzle chamber 191 becomes shorter toward the tip side.

As shown in FIG. 7, the upper lip portion 110 and the lower lip portion 120 come into contact with each other at a position between the nozzle chamber 191 and the gas header chamber 192 in the gas wiping nozzle 10. As a result, the nozzle chamber 191 and the gas header chamber 192 are separated inside the gas wiping nozzle 10. Between the nozzle chamber 191 and the gas header chamber 192, a communication hole 113 and a communication hole 123 that communicate the nozzle chamber 191 and the gas header chamber 192 are provided. Specifically, the communication holes 113 and the communication holes 123 are provided in the upper lip portion 110 and the lower lip portion 120 between the nozzle chamber 191 and the gas header chamber 192, respectively, penetrating from the rear end side to the front end side. .. As a result, the side opposite to the slit 140 in the nozzle chamber 191 and the gas header chamber 192 are communicated with each other by the communication holes 113 and the communication holes 123.

A plurality of communication holes 113 and 123 communication holes 123 are arranged side by side along the width direction of the steel strip 2. The cross-sectional shape of the communication hole 113 and the communication hole 123 may be, for example, a circular shape. The cross-sectional shapes of the communication holes 113 and the communication holes 123 are not limited to the above examples, and may be other shapes. Each of the communication hole 113 and the communication hole 123 corresponds to the second communication hole according to the present invention.

On the rear end side of the gas wiping nozzle 10, an introduction hole (not shown) for communicating the gas header chamber 192 and the outside and introducing gas into the gas header chamber 192 is provided. For example, a conduction hole is provided on the rear end side of the upper lip portion 110 so as to penetrate in the vertical direction. The gas introduced into the gas header chamber 192 is configured to be introduced into the nozzle chamber 191 through the communication holes 113 and 123. Specifically, the gas header chamber 192 functions as a gas header, and the gas introduced into the gas header chamber 192 is rectified and introduced into the nozzle chamber 191 by passing through the communication holes 113 and 123. Further, the nozzle chamber 191 functions as a pressure equalizing chamber, and the gas introduced into the nozzle chamber 191 passes through the communication hole 171 of the fixing member 170 described later and is uniform over the entire longitudinal direction of the slit 140. It is injected at a high pressure.

Further, the upper lip portion 110 and the lower lip portion 120 are fixed to each other in the vertical direction by screw fastening with bolts 151, 152 and nuts 161, 162 at positions where they are in contact with each other. Specifically, the upper lip portion 110 and the lower lip portion 120 are fixed in the vertical direction by bolts 152 and nuts 162 at positions on the rear end side of the gas header chamber 192 in the gas wiping nozzle 10. A plurality of pairs of bolts 152 and nuts 162 may be arranged side by side along the width direction of the steel strip 2. Further, the upper lip portion 110 and the lower lip portion 120 are fixed in the vertical direction by bolts 151 and nuts 161 at positions between the nozzle chamber 191 and the gas header chamber 192 in the gas wiping nozzle 10. A plurality of pairs of bolts 151 and nuts 161 may be arranged side by side along the width direction of the steel strip 2. The upper lip portion 110 and the lower lip portion 120 may be fixed to each other at positions where they come into contact with each other by a method different from screw fastening.

The lower portion of the tip portion 111 of the upper lip portion 110 and the upper portion of the tip portion 121 of the lower lip portion 120 face each other with a vertical gap on the central side in the width direction of the steel strip 2. Specifically, the central portion 115 in the width direction of the steel strip 2 in the lower portion of the tip portion 111 of the upper lip portion 110 is located above the other portion in the lower portion of the tip portion 111. On the other hand, the central portion 125 in the width direction of the steel strip 2 in the upper portion of the tip portion 121 of the lower lip portion 120 is located lower than the other portion in the upper portion of the tip portion 121. In this way, the portion 115 of the upper lip portion 110 and the portion 125 of the lower lip portion 120 are recessed in the lower portion of the tip portion 111 of the upper lip portion 110 and the upper portion of the tip portion 121 of the lower lip portion 120, respectively. Therefore, the portion 115 at the lower part of the tip portion 111 of the upper lip portion 110 and the portion 125 at the upper part of the tip portion 121 of the lower lip portion 120 face each other with a gap in the vertical direction. As a result, as shown in FIGS. 5 and 7, a slit 140 is formed between the tip 111 of the upper lip 110 and the tip 121 of the lower lip 120 as an outlet for the gas injected from the nozzle chamber 191. Will be done. Specifically, the slit 140 extends in the width direction of the steel strip 2.

Further, the lower portion of the tip portion 111 of the upper lip portion 110 and the upper portion of the tip portion 121 of the lower lip portion 120 come into contact with each other on both end sides in the width direction of the steel strip 2. As a result, the slit 140 is defined in the longitudinal direction.

The slit gap of the slit 140 is appropriately set based on various parameters so that the basis weight of the molten metal with respect to the steel strip 2 becomes a desired value. As the parameters, for example, various dimensions of the gas wiping nozzle 10, the internal pressure of the nozzle chamber 191, the positional relationship between the gas wiping nozzle 10 and the steel strip 2 and the like may be applicable. The dimensions of the slit 140 in the longitudinal direction can be appropriately set according to the width of the steel strip 2.

The fixing member 170 is provided on the slit 140 side in the nozzle chamber 191 and is fixed to the upper lip portion 110 and the lower lip portion 120.

The fixing member 170 has, for example, a rectangular parallelepiped shape, and extends from one end side to the other end side of the steel strip 2 of the gas wiping nozzle 10 in the width direction. Since various shapes can be applied as the shape of the fixing member 170, the shape of the fixing member 170 is not limited to the above example.

For example, as shown in FIGS. 5 to 7, the upper lip portion 110 and the lower lip portion 120 are provided with a groove portion 117 and a groove portion 127 at positions corresponding to the fixing member 170. Specifically, the groove portion 117 is provided on the slit 140 side in the portion of the inner peripheral portion of the upper lip portion 110 that defines the nozzle chamber 191. The groove portion 117 extends from one end side to the other end side of the steel strip 2 in the upper lip portion 110 in the width direction. The groove portion 117 has a cross-sectional shape (for example, a U shape) corresponding to the shape of the upper portion of the fixing member 170. On the other hand, the groove portion 127 is provided on the slit 140 side in the portion of the inner peripheral portion of the lower lip portion 120 that defines the nozzle chamber 191. The groove portion 127 extends from one end side to the other end side in the width direction of the steel strip 2 in the lower lip portion 120. The groove portion 127 has a cross-sectional shape (for example, a U shape) corresponding to the shape of the lower portion of the fixing member 170.

The upper portion of the fixing member 170 is fitted into the groove portion 117 of the upper lip portion 110. Further, the lower portion of the fixing member 170 is fitted into the groove portion 127 of the lower lip portion 120. The fixing member 170 is fixed to the upper lip portion 110 and the lower lip portion 120 in a state of being fitted to the groove portion 117 and the groove portion 127 in this way, for example. Since the groove portion 117 and the groove portion 127 are provided for facilitating positioning and attachment of the fixing member 170 to each upper lip portion, they may be omitted from the configuration of each lip portion.

The fixing member 170 is fixed to the upper lip portion 110 and the lower lip portion 120 by, for example, screwing with bolts. Since various methods can be applied as a method of fixing the fixing member 170 to the upper lip portion 110 and the lower lip portion 120, the fixing method of the fixing member 170 to the upper lip portion 110 and the lower lip portion 120 is an example. Not limited. The fixing member 170 is preferably removably fixed to the upper lip portion 110 and the lower lip portion 120. Thereby, the fixing member 170 can be easily removed from the gas wiping nozzle 10 and attached to the gas wiping nozzle 10.

For example, as shown in FIGS. 6 and 7, screw mounting holes 173 having female screw portions are provided at the upper and lower portions of the fixing member 170. A plurality of screw mounting holes 173 are arranged side by side in the upper portion and the lower portion of the fixing member 170 along the width direction of the steel strip 2.

Further, the upper lip portion 110 and the lower lip portion 120 are provided with a counterbore hole through which the bolt 180 penetrates and a screw insertion hole which is a so-called stupid hole at a position corresponding to the screw mounting hole 173 of the fixing member 170. Specifically, a plurality of counterbore holes 119 are arranged side by side along the width direction of the steel strip 2 in the upper portion of the outer peripheral portion of the upper lip portion 110 above the fixing member 170. Each counterbore hole 119 is communicated with the groove portion 117 by a screw insertion hole 118. On the other hand, a plurality of counterbore holes 129 are arranged side by side along the width direction of the steel strip 2 in the lower portion of the fixing member 170 in the outer peripheral portion of the lower lip portion 120. Each counterbore hole 129 is communicated with the groove portion 127 by a screw insertion hole 128.

Bolts 180 are inserted into the upper lip portion 110 and the lower lip portion 120 from the outside, respectively. Specifically, the bolt 180 is inserted into the screw insertion hole 118 of the upper lip portion 110 from the counterbore hole 119 side. On the other hand, the bolt 180 is inserted into the screw insertion hole 128 of the lower lip portion 120 from the counterbore hole 129 side. Further, the bolt 180 through which the screw insertion hole 118 of the upper lip portion 110 is inserted is screwed into the screw attachment hole 173 provided in the upper part of the fixing member 170. On the other hand, the bolt 180 through which the screw insertion hole 128 of the lower lip portion 120 is inserted is screwed into the screw mounting hole 173 provided in the lower part of the fixing member 170. The fixing member 170 is fixed to the upper lip portion 110 and the lower lip portion 120 by, for example, the bolt 180 being screwed into the fixing member 170 in this way.

The head 181 of the bolt 180 is housed in the counterbore holes 119 and the counterbore holes 129 formed on the outer peripheral portions of the upper lip portion 110 and the lower lip portion 120, respectively. The counterbore holes 119 and counterbore holes 129 are closed by the sealing member 185. The seal member 185 has a shape corresponding to each counterbore hole. The seal member 185 can be fixed to each lip portion by various fixing methods such as screw fastening or adhesion using an adhesive. Thereby, it is possible to prevent the head 181 of the bolt 180 from being exposed to the outside at the outer peripheral portion of each lip portion. Therefore, it is possible to prevent the formation of a stepped portion on the tip end side of the outer peripheral portion of each lip portion. When a step portion is formed on the tip end side of the outer peripheral portion of each lip portion, the flow of gas after being injected from the slit 140 may become unstable in the vicinity of the outer peripheral portion of the gas wiping nozzle 10. Therefore, by suppressing the formation of such a stepped portion, the flow of gas after being injected from the slit 140 can be stabilized.

As described above, the counterbore hole and the screw insertion hole provided in each lip portion are located at positions corresponding to the screw mounting hole 173 of the fixing member 170. Further, a plurality of screw mounting holes 173 provided in the fixing member 170 are specifically arranged side by side along the width direction of the steel strip 2. For example, as shown in FIG. 6, two screw mounting holes 173 are located at positions corresponding to both ends of each lip portion in the width direction of the steel strip 2, and four screw mounting holes 173 correspond to the both ends. It is located between the positions to be used. Therefore, the fixing member 170 can be fixed to the portions facing each other via the nozzle chambers 191 of the upper lip portion 110 and the lower lip portion 120.

In the fixing member 170, a plurality of communication holes 171 communicating the slit 140 side and the opposite side of the slit 140 with respect to the fixing member 170 are arranged side by side along the width direction of the steel strip 2. The cross-sectional shape of the communication hole 171 may be, for example, a circular shape. The cross-sectional shape of the communication hole 171 is not limited to the above example, and may be another shape. The communication hole 171 corresponds to the first communication hole according to the present invention.

The gas introduced into the nozzle chamber 191 through the communication holes 113 and 123 passes through the communication holes 171 of the fixing member 170 and reaches the slit 140. A plurality of the communication holes 171 are arranged side by side along the width direction of the steel strip 2 to have a function of rectifying the gas passing through the communication holes 171. Therefore, it is possible to prevent the gas flow inside the nozzle chamber 191 from becoming non-uniform in the width direction of the steel strip 2.

The communication holes 171 may be arranged side by side at equal intervals. Thereby, the effect of rectifying the gas by the communication hole 171 can be further improved. Therefore, it is possible to more effectively prevent the gas flow inside the nozzle chamber 191 from becoming non-uniform in the width direction of the steel strip 2.

The communication holes 171 may be arranged side by side at shorter intervals than the communication holes 113 and the communication holes 123. Specifically, as shown in FIG. 6, the distance D17 between the adjacent communication holes 171 may be shorter than the distance D12 between the adjacent communication holes 123. The distance between the adjacent communication holes 113 may coincide with the distance D12. By arranging the communication holes 171 side by side at shorter intervals than the communication holes 113 and the communication holes 123, the effect of rectifying the gas by the communication holes 171 is compared with the effect of rectifying the gas by the communication holes 113 and the communication holes 123. Can be made higher. As a result, it is possible to more effectively prevent the gas flow inside the nozzle chamber 191 from becoming non-uniform in the width direction of the steel strip 2.

As described above, the gas wiping nozzle 10 according to the present embodiment is provided with a fixing member 170 provided on the slit 140 side in the nozzle chamber 191 and fixed to the upper lip portion 110 and the lower lip portion 120. Therefore, the upper lip portion 110 and the lower lip portion 120 are fixed at positions corresponding to the tip end side in the nozzle chamber 191 in the thickness direction of the steel strip 2. As a result, the distance L10 in the thickness direction of the steel strip 2 from the portion where the upper lip portion 110 and the lower lip portion 120 are fixed to each other to the tip portion of the slit 140 is compared with the case where the fixing member 170 is not provided. Can be shortened. Therefore, even when reassembling each part in order to replace a part or all of the parts constituting the gas wiping nozzle 10 for maintenance, it is possible to suppress the variation of the slit gap after assembly for each assembly. can do. Further, even when the gas pressure supplied to the nozzle chamber 191 of the gas wiping nozzle 10 is increased in order to control the basis weight amount to a desired value while increasing the transport speed of the steel strip 2, the nozzle It is possible to suppress the expansion of the slit gap due to the increase in the internal pressure of the chamber 191.

Further, in the fixing member 170, a plurality of communication holes 171 communicating the slit 140 side and the opposite side of the slit 140 with respect to the fixing member 170 are arranged side by side along the width direction of the steel strip 2. As a result, it is possible to prevent the gas flow inside the nozzle chamber 191 from becoming non-uniform in the width direction of the steel strip 2.

As described above, according to the present embodiment, while suppressing the gas flow inside the nozzle chamber 191 from becoming non-uniform in the width direction of the steel strip 2, the change in the slit gap, which is difficult to adjust, is suppressed. can do. Therefore, the collision pressure of the gas with respect to the steel strip 2 can be stabilized. As a result, it is possible to stabilize the basis weight of the molten metal with respect to the steel strip 2.

Further, as described above, the fixing member 170 is specifically fixed to the portions of the upper lip portion 110 and the lower lip portion 120 which face each other via the nozzle chambers 191. Here, when the internal pressure of the nozzle chamber 191 is increased in order to increase the gas pressure supplied to the nozzle chamber 191 of the gas wiping nozzle 10, the center of the steel strip 2 in the gas wiping nozzle 10 in the width direction is particularly large. The slit gap tends to widen on the side. Therefore, by fixing the fixing member 170 to the portions of the upper lip portion 110 and the lower lip portion 120 that face each other via the nozzle chamber 191, the slit gap is widened due to the increase in the internal pressure of the nozzle chamber 191. It can be suppressed more effectively.

In order to confirm the effect of the present invention, an example using an analysis model corresponding to the gas wiping nozzle 10 according to the embodiment of the present invention and a comparative example using an analysis model corresponding to a gas wiping nozzle different from the gas wiping nozzle 10. For each, the relationship between the gas pressure supplied to the nozzle chamber and the amount of expansion of the slit gap (hereinafter, also referred to as the opening amount) and the distribution of the collision pressure of gas with respect to the steel strip 2 in the width direction of the steel strip 2. Numerical analysis was performed to evaluate. Specifically, as the numerical analysis, stress analysis (three-dimensional solid analysis) using general-purpose software was performed.

In the embodiment, an analysis model corresponding to the gas wiping nozzle 10 according to the present embodiment described with reference to FIGS. 5 to 7 was used. On the other hand, in the comparative example, an analysis model corresponding to the gas wiping nozzle 90 according to the reference example described with reference to FIGS. 2 to 4 was used. Various dimensions such as the thickness of the upper lip portion and the lower lip portion and various dimensions of the nozzle chamber and the gas header chamber are substantially the same between the models of the examples and the comparative examples.

First, the result of numerical analysis on the relationship between the gas pressure supplied to the nozzle chamber and the opening amount will be described. In the numerical analysis, the amount of mouth opening when the gas pressure supplied to the nozzle chamber takes each numerical value was determined for each of the examples and the comparative examples. Specifically, for each of the models of Examples and Comparative Examples, the displacement amount of the nozzle tip when a pressure corresponding to each gas pressure was applied to the inner wall of the nozzle chamber was obtained. In addition, numerical analysis was performed on each of the models of Examples and Comparative Examples, with the slit gap before applying pressure as 0.6 [mm]. In the examples and comparative examples, numerical analysis was performed for the cases where 50 [kPa], 100 [kPa], 130 [kPa], 170 [kPa] and 200 [kPa] were applied as the gas pressures supplied to the nozzle chamber, respectively. went.

FIG. 8 is an explanatory diagram showing the analysis result of the opening amount for each of the gas pressures supplied to the nozzle chamber. Specifically, in the comparative example, when the gas pressures are 50 [kPa], 100 [kPa], 130 [kPa], 170 [kPa] and 200 [kPa], the opening amount is 0.023 [kPa], respectively. It was [mm], 0.029 [mm], 0.033 [mm], 0.044 [mm] and 0.049 [mm]. On the other hand, in the examples, when the gas pressures are 50 [kPa], 100 [kPa], 130 [kPa], 170 [kPa] and 200 [kPa], the opening amount is 0.00090 [mm], respectively. It was 0.0011 [mm], 0.0013 [mm], 0.0017 [mm] and 0.0019 [mm].

As shown in FIG. 8, in the comparative example, it was confirmed that the mouth opening amount was a relatively large value for each gas pressure. Moreover, in the comparative example, it was confirmed that the amount of mouth opening increased remarkably as the gas pressure increased. The relationship between the gas pressure and the opening amount in the comparative example is attributed to the fact that the upper lip portion 910 and the lower lip portion 920 form a cantilever structure supported on the rear end side as described above. Conceivable.

On the other hand, in the examples, it was confirmed that the mouth opening amount was a relatively small value for each gas pressure. Further, in the examples, it was confirmed that the amount of mouth opening was substantially constant regardless of the magnitude of the gas pressure. Therefore, it was confirmed that the increase in the amount of mouth opening due to the increase in gas pressure was suppressed. Therefore, it was confirmed that the change of the slit gap, which is difficult to adjust, can be suppressed.

Next, the result of the numerical analysis about the distribution of the collision pressure of the gas with respect to the steel strip 2 in the width direction of the steel strip 2 will be described. In the numerical analysis, the set values of the gas pressure supplied to the nozzle chamber were matched in the examples and the comparative examples, and the distribution of the collision pressure of the gas in the width direction of the steel strip 2 was obtained. Specifically, for each model of the example and the comparative example, the distribution of the collision pressure of the gas when the pressure corresponding to the set value of the gas pressure was applied to the inner wall of the nozzle chamber was obtained. As the distribution of the gas collision pressure, specifically, the gas collision pressure at each position in the width direction of the steel strip 2 in the gas wiping nozzle was obtained. In addition, a relatively high pressure was set as the set value of the gas pressure.

FIG. 9 is an explanatory diagram showing the analysis result of the collision pressure of the gas with respect to the steel strip 2 at each position in the width direction of the steel strip 2 in the gas wiping nozzle. Note that FIG. 9 shows the analysis result of the collision pressure of the gas for a part between both ends of the steel strip 2 in the width direction of the gas wiping nozzle. Specifically, in the embodiment, the collision pressure was a value near 162.5 [kPa] at each position in the width direction of the steel strip 2 in the gas wiping nozzle. On the other hand, in the comparative example, the collision pressure from one end side to the other end side in the width direction of the steel strip 2 in the gas wiping nozzle ranges from a value near 162.5 [kPa] to a value below 160 [kPa]. It was distributed in the range.

As described above, in the comparative example, it was confirmed that the collision pressure was lower in each position of the steel strip 2 in the width direction as compared with the embodiment. In the comparative example, as described above, the amount of mouth opening increases remarkably as the gas pressure increases. Therefore, by setting a relatively high pressure as the set value of the gas pressure, the opening amount of the mouth becomes a relatively large value in the comparative example. As a result, it is considered that the collision pressure in the comparative example was lower than that in the example at each position of the steel strip 2 in the width direction.

Further, in the comparative example, a peak was confirmed in which the collision pressure locally increased in the width direction of the steel strip 2. For example, in FIG. 9, in the analysis result of the comparative example, the peak P1 and the peak P2 whose collision pressure is higher than that of the surroundings are shown. In the comparative example, these peaks are caused by the fact that the gas flow inside the nozzle chamber becomes non-uniform in the width direction of the steel strip 2 due to the setting of a relatively high gas pressure. It is probable that it occurred.

On the other hand, in the examples, as shown in FIG. 9, it was confirmed that the variation in the gas collision pressure in the width direction of the steel strip 2 was at least equal to or less than the variation in the comparative example. Therefore, in the examples, it was confirmed that it is possible to prevent the gas flow inside the nozzle chamber 191 from becoming non-uniform in the width direction of the steel strip 2. As described above, the function of ensuring the uniformity of the gas flow inside the nozzle chamber 191 is realized by the communication holes 171 arranged side by side in the fixing member 170 along the width direction of the steel strip 2.

Therefore, in the embodiment, it is possible to suppress the change in the slit gap, which is difficult to adjust, while suppressing the gas flow inside the nozzle chamber 191 from becoming non-uniform in the width direction of the steel strip 2. confirmed. Therefore, according to the gas wiping nozzle 10 according to the embodiment of the present invention, it is possible to stabilize the basis weight of the molten metal with respect to the steel strip 2.

<4. Summary>
As described above, the gas wiping nozzle 10 according to the present embodiment is provided with a fixing member 170 provided on the slit 140 side in the nozzle chamber 191 and fixed to the upper lip portion 110 and the lower lip portion 120. As a result, the distance L10 in the thickness direction of the steel strip 2 from the portion where the upper lip portion 110 and the lower lip portion 120 are fixed to each other to the tip portion of the slit 140 is compared with the case where the fixing member 170 is not provided. Can be shortened. Therefore, when reassembling a part or all of the parts constituting the gas wiping nozzle 10, or in order to control the basis weight amount to a desired value while increasing the transport speed of the steel strip 2, the nozzle chamber of the gas wiping nozzle 10 is used. It is possible to suppress changes in the slit gap that are difficult to adjust, which may occur when the gas pressure supplied to the 191 is increased.

Further, in the fixing member 170, a plurality of communication holes 171 communicating the slit 140 side and the opposite side of the slit 140 with respect to the fixing member 170 are arranged side by side along the width direction of the steel strip 2. As a result, it is possible to prevent the gas flow inside the nozzle chamber 191 from becoming non-uniform in the width direction of the steel strip 2.

As described above, according to the present embodiment, while suppressing the gas flow inside the nozzle chamber 191 from becoming non-uniform in the width direction of the steel strip 2, the change in the slit gap, which is difficult to adjust, is suppressed. can do. Therefore, the collision pressure of the gas with respect to the steel strip 2 can be stabilized. As a result, it is possible to stabilize the basis weight of the molten metal with respect to the steel strip 2.

In the above description, an example in which the nozzle chamber 191 and the gas header chamber 192 are formed on the front end side and the rear end side of the gas wiping nozzle 10 respectively has been described. However, as a reference example, the gas header chamber 192 is based on the configuration of the gas wiping nozzle 10. May be omitted. In that case, the communication hole 113 and the communication hole 123 that communicate the nozzle chamber 191 and the gas header chamber 192 are omitted from the configuration of the upper lip portion 110 and the lower lip portion 120.

Further, in the above description, an example in which the slit 140 is formed by the portions 115 and 125 recessed in the lower portion of the tip portion 111 of the upper lip portion 110 and the upper portion of the tip portion 121 of the lower lip portion 120, respectively, has been described. The slit 140 may be formed by utilizing a shim. In that case, the shim is sandwiched in the vertical direction by, for example, the upper lip portion 110 and the lower lip portion 120, and comes into contact with a portion of each lip portion other than the central side in the width direction of the steel strip 2. As a result, the slit 140 can be formed by providing a gap corresponding to the thickness of the shim between the tip portion 111 of the upper lip portion 110 and the tip portion 121 of the lower lip portion 120. When such a shim is provided on the gas wiping nozzle 10, the shape of the shim or the fixing member 170 is appropriately set in order to prevent interference between the shim and the fixing member 170. Further, when such a shim is provided on the gas wiping nozzle 10, the portion 115 and the portion 125 may be omitted from the configuration of the upper lip portion 110 and the lower lip portion 120.

Although the preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, the present invention is not limited to these examples. It is clear that a person having ordinary knowledge in the field of technology to which the present invention belongs can come up with various modifications or applications within the scope of the technical idea described in the claims. , These are also naturally understood to belong to the technical scope of the present invention.

1 Continuous molten metal plating equipment 2 Steel strip 3 Plating bath 4 Plating tank 5 Snout 6 Sink roll 7, 8 Support roll 9 Top roll 10 Gas wiping nozzle 110 Upper lip part 113 Communication hole 117 Groove part 118 Screw insertion hole 119 Counterbore hole 120 Lower Lip 123 Communication hole 127 Groove 128 Screw insertion hole 129 Counterbore hole 140 Slit 151,152 Bolts 161, 162 Nut 170 Fixing member 171 Communication hole 173 Screw mounting hole 180 Bolt 181 Head 185 Sealing member 191 Nozzle chamber 192 Gas header chamber

Claims (4)

A gas wiping nozzle that adjusts the film thickness of the molten metal film adhering to the surface of the steel strip by blowing gas onto the steel strip pulled upward from the molten metal plating bath.
A first lip portion and a second lip portion that are provided so as to face each other and form a nozzle chamber into which the gas is introduced, and a second lip portion.
As an outlet for the gas injected from the nozzle chamber, a slit formed between the steel strip-side end of each of the first lip portion and the second lip portion, and
A fixing member provided on the slit side in the nozzle chamber and fixed to the first lip portion and the second lip portion.
With
A plurality of first communication holes for communicating the slit side and the opposite side of the slit with respect to the fixing member are arranged side by side in the fixing member along the width direction of the steel strip .
Wherein the inner side of the first lip and the second lip portion, gas header chamber in which the gas to be introduced into the nozzle chamber is introduced Ru is further formed,
Gas wiping nozzle. The first communication holes are arranged side by side at equal intervals.
The gas wiping nozzle according to claim 1. Between the front Symbol nozzle chamber and the gas header chamber, a second communicating hole communicating the slit and the opposite side and the gas header chamber in the nozzle chamber is more arranged along the width direction of the steel strip,
The first communication holes are arranged side by side at shorter intervals as compared with the second communication holes.
The gas wiping nozzle according to claim 1 or 2. Bolts are inserted into the first lip portion and the second lip portion from the outside, respectively.
The fixing member is fixed to the first lip portion and the second lip portion by screwing the bolt into the fixing member.
Counterbore holes for accommodating the heads of the bolts are formed in the first lip portion and the outer peripheral portion of the second lip portion.
The counterbore hole is closed by a sealing member.
The gas wiping nozzle according to any one of claims 1 to 3.

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