Patent Application
20160312356
The present disclosure relates to a heating apparatus configured to generate coating vapor (gas) to coat a continuously moving base metal (steel sheet) with the coating vapor by an evaporation coating method, and more particularly, to a heating apparatus and a coating machine including the heating apparatus, the heating apparatus employing a liquid-phase supply method in which a coating material supplied to a nozzle unit is heated and phase-changed from solid to liquid, and then the liquid-phase coating material is discharged to a heating unit so as to smoothly and stably generate coating vapor. In addition, the heating apparatus is configured to preheat a solid-phase coating material and prevent clogging of a coating material supply tube so as to coat a (rapidly moving) steel sheet with high quality and productivity.
For example, in a vacuum evaporation coating method known in the related art, a substrate such as a steel sheet may be coated in a vacuum with a coating material such as metal vapor while the substrate is continuously fed (at a high speed).
In such a vacuum evaporation coating process, a solid-phase or liquid-phase coating material may be heated and evaporated by various methods to obtain coating vapor (gas), and a steel sheet may be coated by depositing the coating vapor on the steel sheet.
For example, vacuum evaporation coating methods for continuously coating a substrate (such as a steel sheet) may be classified according to heating techniques into thermal evaporation methods and electron beam evaporation methods.
In addition, electromagnetic (levitation) evaporation methods have been recently researched for high speed evaporation coating.
In an electromagnetic evaporation method, a coating material is surrounded by an electromagnetic coil, and a high-frequency AC current is applied from a high-frequency power supply to the electromagnetic coil to generate an AC electromagnetic field. Then, the coating material is levitated and heated by the AC electromagnetic field, thereby generating coating vapor such as metal vapor in large amounts with less thermal loss compared to a method of generating metal vapor using a crucible. Therefore, a (rapidly) moving substrate such as a steel sheet may be coated with the coating vapor.
To this end, a heating apparatus (evaporating apparatus) capable of generating coating vapor is required to coat a steel sheet continuously fed in a vacuum, and the supply of a coating material (to be evaporated to generate coating vapor) is also required for continuous coating.
Coating material supply methods may be classified into solid-phase supply methods and liquid-phase supply methods, and the liquid-phase supply methods may be further classified into mechanical methods, height difference methods, pressure difference methods, etc.
Examples of the mechanical methods include a piston method (disclosed in US Patent Application Publication No. 2005-0229856), a magneto hydrodynamic (MHD) pump method using electromagnetism (disclosed in Korean Patent Application Laid-open Publication No. 2007-0015923), and a screw method (disclosed in Japanese Patent Application Laid-open Publication No. 2010-189739).
An example of the height difference methods is disclosed in Korean Patent Application Laid-open Publication No. 2009-0074064, and an example of the pressure difference methods is disclosed in Japanese Patent Application Laid-open Publication No. S55-154537.
However, the disclosed liquid-phase supply methods cause equipment erosion (abrasion) because of the temperature or chemical properties of liquid-phase coating materials.
In a typical solid-phase supply method, a solid wire is supplied as a coating material. However, this method causes a decrease in the temperature of coating vapor generated inside an electromagnetic coil.
An aspect of the present disclosure may provide a heating apparatus configured to smoothly and stably generate coating vapor by a liquid-phase supply method in which a solid-phase coating material supplied to a nozzle unit is heated and melted to obtain a liquid-phase coating material, and the liquid-phase coating material is discharged to a heating unit.
An aspect of the present disclosure may also provide a heating apparatus configured to preheat a coating material to induce smooth phase change from solid to liquid and to prevent clogging of a coating material supply tube and backflow of coating vapor.
An aspect of the present disclosure may also provide a coating machine configured to coat a rapidly moving steel sheet with high quality and productivity by using the heating apparatus.
According to an aspect of the present disclosure, a heating apparatus may include: a heating unit configured to heat a supplied coating material so as to generate coating vapor to be deposited on an coating target object; and a nozzle unit disposed inside the heating unit to receive the coating material supplied in solid phase, wherein the solid-phase coating material may be heated and phase-changed to liquid in the nozzle unit, and the liquid-phase coating material may be discharged from the nozzle unit to the heating unit.
According to another aspect of the present disclosure, a coating machine may include: the heating apparatus; a vacuum chamber partially or entirely surrounding the heating apparatus so as to coat a coating target object with coating vapor generated by the heating apparatus when the coating target object passes through the vacuum chamber maintained in a vacuum state; and a coating vapor discharge tube connected to the coating vapor generating tube of the heating apparatus and including a discharge opening through which the coating vapor is discharged toward the coating target object.
According to embodiments of the present disclosure, the heating apparatus employs a liquid-phase supply method in which coating vapor is generated with a small temperature decrease by receiving a solid-phase coating material in a nozzle unit, heating the solid-phase coating material in the nozzle unit to obtain a liquid-phase coating material, and supplying the liquid-phase coating material to a heating unit.
In addition, according to the embodiments of the present disclosure, the heating apparatus preheats a solid-phase coating material to induce a smooth phase change from solid to liquid and prevents clogging of the coating material supply tube or backflow of coating vapor into a certain region (for example, into the coating material supply tube).
Therefore, according to the embodiments of the present disclosure, the coating machine including the heating apparatus may coat a rapidly moving steel sheet with high quality and productivity.
Exemplary embodiments of the present disclosure will now be described in detail (with reference to the accompanying drawings). The disclosure may, however, be exemplified in many different forms and should not be construed as being limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the disclosure to those skilled in the art (in the drawings, the shapes and dimensions of elements may be exaggerated for clarity).
First,
The coating machine 200 illustrated in
In the following descriptions of exemplary embodiments, the case in which a coating target object is a (rapidly) moving steel sheet 210 will only be described for clarity of description. In addition, a coating material (coating medium) may be referred to as a solid-phase coating material 10 when the coating material is in the solid phase, a liquid-phase coating material 12 after the solid-phase coating material 10 is heated and phase-changed (melted) to liquid, and coating vapor 14 after the liquid-phase coating material 12 is heated and evaporated as deposition vapor (gas).
In addition, the term “phase change” refers to a process in which a solid-phase coating material 10 is heated and melted into a liquid-phase coating material 12.
As illustrated in
For example, as illustrated in
Each of the coating machines 200 of the embodiments may include a vacuum chamber 220 hermetically surrounding at least a portion of a heating unit 20 of the heating apparatus 1 and at least a portion of a coating material supply tube 52 connected to a nozzle unit 50 of the heating apparatus 1 described in detail with reference to
In addition, transfer rolls 222 are disposed at an entrance and an exit of the vacuum chamber 220 so as to continuously and rapidly transfer a steel sheet 210 as a coating target object. The transfer rolls 222 may also act as structures sealing the entrance and exit of the vacuum chamber 220.
In addition, each of the coating machines 200 of the exemplary embodiments may further include a coating vapor discharge tube 230 connected to a coating vapor generating tube 40 of the heating unit 20 (described later in detail), and the coating vapor discharge tube 230 includes a discharge opening 232 so as to discharge coating vapor 14 toward a surface of a steel sheet 210.
A heating wire 234 or another heating element may be disposed around the coating vapor discharge tube 230 to maintain the coating vapor discharge tube 230 at a constant temperature and thus to prevent cooling of coating vapor 14.
Therefore, in each of the coating machines 200 of the exemplary embodiments, coating vapor 14 generated by the heating apparatus 1 may be discharged through the discharge opening 232 of the coating vapor discharge tube 230, and the discharged coating vapor 14 may be deposited on a steel sheet 210 moving beside the discharge opening 232, thereby coating the steel sheet 210.
Although tubes are schematically illustrated in the accompanying drawings, the tubes may have lengths corresponding to the maximum width of steel sheets.
Next, the heating apparatus 1 will be described with reference to
First, referring to an exemplary embodiment illustrated in
That is, in the heating apparatus 1 of the exemplary embodiment, a solid-phase coating material 10 prepared in the form of ingots falls into the nozzle unit 50 disposed inside the heating unit 20, and the solid-phase coating material 10 is heated and phase-changed into a liquid-phase coating material 12. Then, the liquid-phase coating material 12 is discharged from the nozzle unit 50 to the coating vapor generating tube 40 of the heating unit 20 where the liquid-phase coating material 12 is further heated to generate coating vapor 14. Finally, the coating vapor 14 is discharged through the discharge opening 232 of the coating vapor discharge tube 230 and deposited on a (rapidly) moving steel sheet 210, and thus the steel sheet 210 is coated.
Therefore, the heating apparatus 1 according to the exemplary embodiment is free from problems of the related art such as erosion (damage) of equipment caused by a liquid-phase coating material directly supplied to a heating unit, or a temperature decrease of a coating material occurring when the coating material is supplied in the form of a wire.
That is, a solid-phase coating material 10 is supplied to the heating unit 20 in the form of ingots having a predetermined size for ease in handling and supply, and in a state in which the solid-phase coating material 10 is initially accommodated in the nozzle unit 50 (described later in detail), the solid-phase coating material 10 is heated and phase-changed into a liquid-phase coating material 12. Then, the liquid-phase coating material 12 is discharged to the heating unit 20 through nozzle openings formed in a lateral wall of the nozzle unit 50. Therefore, coating vapor 14 may be smoothly generated, and since a liquid-phase coating material causing erosion of equipment is not initially supplied, problems such as equipment erosion may be prevented.
As illustrated in
Therefore, if power is applied to the electromagnetic coils 30 including an upper electromagnetic coil 32 having a predetermined number of turns and a lower electromagnetic coil 34 properly spaced apart from the upper electromagnetic coil 32 and having a predetermined number of turns, a coating material may be heated by an electromagnetically induced current, and thus coating vapor 14 may be generated. In this manner, the heating apparatus 1 of the exemplary embodiment may generate coating vapor 14 and may coat a steel sheet 210 with the coating vapor 14.
In detail, a solid-phase coating material 10 placed inside the nozzle unit 50 after falling along the nozzle unit 50 is phase-changed into a liquid-phase coating material 12 owing to electromagnetic force generated inside the electromagnetic coils 30 by a high-frequency current applied to the electromagnetic coils 30, and the liquid-phase coating material 12 is discharged through the nozzle openings 54 of the nozzle unit 50 to the coating vapor generating tube 40 where the liquid-phase coating material 12 is further heated by electromagnetic induction and thus phase-changed into coating vapor 14 (metal vapor).
Then, the coating vapor 14 is discharged through the discharge opening 232 of the coating vapor discharge tube 230 connected to the coating vapor generating tube 40 of the coating machine 200 and is deposited on a steel sheet 210 which is being transferred near the coating vapor discharge tube 230, thereby coating the steel sheet 210 with the coating vapor 14.
As illustrated in
In addition, as illustrated in
Next, with reference to
In detail,
Hereinafter, the nozzle units 50 will be described in detail according to the exemplary embodiments.
First, referring to
Since the nozzle unit 50 is disposed inside the electromagnetic coils 30 of the heating unit 20 and is heated to a high temperature, the nozzle unit 50 may be connected to the lower portion of the coating material supply tube 52 through the connection tube 58 formed of a different material.
As illustrated in
The nozzle 56 has a cylindrical shape with a closed bottom side, and thus a solid-phase coating material 10 falling along the nozzle unit 50 may be accommodated in the nozzle 56.
According to the embodiment illustrated in
Therefore, after a solid-phase coating material 10 supplied through the coating material supply tube 52 is placed on the bottom (not indicated by a reference numeral) of the nozzle 56, electromagnetic force may be applied to heat and melt the solid-phase coating material 10, thus obtaining a liquid-phase coating material 12.
The connection tube 58 connected between the nozzle and the coating material supply tube 52 may have a cylindrical shape, and may be formed of a non-conductive material such as boron nitride. The connection tube 58 formed of a non-conductive material may be connected to the lower portion of the coating material supply tube 52, and the nozzle 56 may be connected to a lower portion of the connection tube 58 to prevent overheating during electromagnetic induction heating.
In addition, since the coating material supply tube 52 extends to a position close to the heating unit 20, the coating material supply tube 52 may be formed of heat-resistant graphite, and may have a cylindrical shape.
However, as illustrated in
As illustrated in
That is, in a state in which a solid-phase coating material 10 is stably accommodated in the nozzle 56 of the nozzle unit 50, the solid-phase coating material 10 may be stably heated and smoothly phase-changed (melted) into a liquid-phase coating material 12. Thus, coating vapor 14 may also be smoothly generated.
Since a liquid-phase coating material 12 is not initially supplied as described above, coating material supply equipment may not be eroded. In addition, since a wire type coating material is not used, a temperature decrease of a coating material may be prevented.
As illustrated in
In detail, as illustrated in
The shock absorber 64 may be a stack of thin heat-resistant sheets capable of absorbing impact force applied by an ingot of a solid-phase coating material 10 falling through the coating material supply tube 10.
For example, the shock absorber 64 disposed in the holder 62 connected to the lower portion of the nozzle 56 having an opened bottom may be formed of a thin, high-purity alumina sheet capable of withstanding high temperatures.
Alternatively, according to an embodiment illustrated in
That is, as illustrated in
In this manner, when ingots of a solid-phase coating material 10 are sequentially supplied, heated, and phase-changed into a liquid-phase coating material 12, the liquid-phase coating material receiving part 66 having a height H from the bottom of the nozzle 56 may be filled with some of the liquid-phase coating material 12. Therefore, once an ingot of the solid-phase coating material 10 is supplied, impact force may be absorbed when subsequent ingots of the solid-phase coating material 10 fall into the nozzle 56.
As illustrated in
Next, as illustrated in
That is, according to the exemplary embodiment illustrated in
As illustrated in
As described above, a liquid-phase coating material 12 obtained by electromagnetically heating an ingot of a solid-phase coating material 10 placed in the nozzle unit 50 may be discharged to the coating vapor generating tube 40 through the nozzle openings 54 of the nozzle 56. That is, after an ingot of a solid-phase coating material 10 is supplied through the coating material supply tube 52, coating vapor 14 may flow backward along the coating material supply tube 52 through the nozzle openings 54.
As described above with reference to
Therefore, a portion of the coating material supply tube 52 located inside the coating vapor discharge tube 230 may be maintained at a relatively high temperature, and thus may not be clogged with coating vapor 14 flowing backward in the portion of the coating material supply tube 52 because the coating vapor 14 is not cooled. However, coating vapor 14 flowing backward in a portion of the coating material supply tube 52 located outside the coating vapor discharge tube 40 may be cooled and phase-changed to become solid, and thus the coating material supply tube 52 may be clogged.
However, according to the embodiment of the present disclosure, if the driving unit (vertical driving cylinder) 72 is operated, the header 74 of the supply tube blockage prevention unit 70 connected to the driving unit 72 through the connecting rod 76 is moved at least to the boundary region A (refer to
In addition, since the header 76 is moved to the boundary region A in the coating material supply tube 52, coating vapor 14 may not be discharged through an upper entrance of the coating material supply tube 52.
Although schematically illustrated in
Although schematically illustrated in the drawings, the coating material supply tube 52 may extend through walls of the vacuum chamber 220 and the coating vapor discharge tube 230 (or the coating vapor generating tube 40) in a hermetically sealed state so as to prevent leakage of coating vapor 14 or introduction of ambient air into the vacuum chamber 220.
Next, referring to
That is, as illustrated in
For example, as illustrated in
In this case, a sealing material 114a may be provided on the blocking plate 114 to securely seal the opening 52a of the coating material supply tube 52.
Therefore, as illustrated in
Basically, backflow of coating vapor 14 may be blocked by downwardly moving the header 72 of the supply tube blockage prevention unit 70 toward the boundary region A between the coating vapor discharge tube 230 and the coating material supply tube 52. However, the blocking plate 114 used to adjust the supply of a solid-phase coating material 10 may also be used to block backflow of coating vapor 14.
For example, if the generation of coating vapor 14 it is required to be increased according to coating conditions, the blocking plate 114 may be moved into the coating material supply tube 52 to receive an intended number of ingots of a solid-phase coating material 10, and may then be moved backward to supply the intended number of ingots of the solid-phase coating material 10 to the nozzle unit 50. In this manner, the supply of the solid-phase coating material 10 may be adjusted using the blocking plate 114.
Next, Referring to
The coating material supply unit 80 illustrated in
As illustrated in
The rotary stack 83 may have a multiple structure, or the coating material containing parts 82 may be vertically formed through the rotary stack 83.
That is, as illustrated in
Therefore, if an ingot of the solid-phase coating material 10 falls through a solid-phase coating material outlet (87) of a casing 88 having an internal space and supported by a support (not shown) on the vacuum chamber 220, a pushing part 89a connected to a rod of a cylinder 89 horizontally disposed with respect to the casing 88 may push the ingot of the solid-phase coating material 10 toward an opposite side of the casing 88, that is, toward the upper entrance of the coating material supply tube 52. Thus, the ingot of the solid-phase coating material 10 may be fed into the nozzle unit 50 through the coating material supply tube 52.
As illustrated in
Alternatively, as illustrated in
That is, the coating material supply units 80 illustrated in
In addition, as illustrated in
That is, as illustrated in
In the embodiment, the preheating unit 100 may preheat a solid-phase coating material 10, and then the solid-phase coating material 10 may be supplied to the nozzle 56 of the nozzle unit 50 through the coating material supply tube 52. Thus, the solid-phase coating material 10 may easily be phase-changed (melted) into a liquid-phase coating material 12 by electromagnetic induction heating, and as a result, coating vapor 14 may be smoothly generated.
According to the embodiment illustrated in
Therefore, as illustrated in
In this case, as illustrated in
According to the exemplary embodiments of the present disclosure, in the heating apparatus 1 of each of the coating machines 200, the nozzle unit 50 in which a solid-phase coating material 10 is accommodated and phase-changed into a liquid-phase coating material 12 may be disposed inside the electromagnetic coils 30 of the heating unit 20 between the upper electromagnetic coil 32 and the lower electromagnetic coil 34 of the electromagnetic coils 30 as illustrated
In addition, in the coating machines 200 according to the exemplary embodiments of the present disclosure, the electromagnetic coils 30 of the heating apparatus 1 may be arranged outside the vacuum chamber 220 and exposed to ambient air as illustrated in
In the case in which the electromagnetic coils 30 are arranged outside the vacuum chamber 220 and exposed to ambient air, the electromagnetic coils 30 may surround an insulative flange 240 coupled to the vacuum chamber 220. That is, the insulative flange 240 may surround the coating vapor generating tube 40 of the heating unit 20 kept in a vacuum and may function as a barrier between the coating vapor generating tube 40 and the electromagnetic coils 30 exposed to ambient air.
As described above, in the heating apparatus 1 and the coating machines 200 including the heating apparatus 1, a liquid-phase supply method is used. According to the liquid-phase supply method, a supplied solid-phase coating material is accommodated in the nozzle 56 and heated to obtain a liquid-phase coating material, and the liquid-phase coating material is supplied to the heating unit 20. Therefore, coating vapor may be generated smoothly and stably. In addition, a supplied solid-phase coating material may be preheated, and backflow of coating vapor may be blocked at a predetermined position so as to prevent clogging of the coating material supply tube 52. Therefore, a rapidly moving steel sheet may be coated with high quality and productivity.
While exemplary embodiments have been shown and described above, the exemplary embodiments should be considered in a descriptive sense only and not for purposes of limitation, and it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present invention as defined by the appended claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2013-0158862 | Dec 2013 | KR | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/KR2013/011855 | 12/19/2013 | WO | 00 |
