MXPA99006537A - Coating plant - Google Patents

Abstract

Una planta de recubrimiento para recubrir el material en forma de tira con material de recubrimiento que se va a recubrir es guiado dentro de un baño de recubrimiento, y es guiado entre dos rodillos de recubrimientos, los cuales están parcialmente sumergidos en el baño de recubrimiento, fuera del baño de recubrimiento y pasando las boquillas de separación en tiras, los apoyos de los rodillos de recubrimiento que están colocados fuera del baño de recubrimiento. Preferiblemente el material en forma de tira es guiado dentro del baño de recubrimiento por medio de uno o más rodillos deflectores de los cuales por lo menos uno estácolocado fuera del baño de recubrimiento.

Description

PLEASE RETIRED The invention relates to a coating plant for coating material in strip form with coating material, in which the strip-like material to be coated is guided inside the coating bath, between two coating rollers, which They are partially submerged in the coating bath, outside the coating bath and pass the separation nozzles in strips. The coating plant for coating strip material has been known in various forms for a long time. The purpose of said plant is to cover the material in the form of a strip of different types, that is to say metal strip, strip of plastic material, strip of fabric or strip of paper, with different coatings of liquid medium, for example zinc fused tin or alloys of the same or coloring material. The coating bath for coating the material in strip form with tin or zinc is in the form of a molten bath in which the materials melt. The coating plant of the type mentioned initially has been known for a long time, for example from J PA 55128570. This coating plant is provided with a deflector roller which guides the strip through the bath and which is completely submerged with its supports in the coating bath. Also two coating rollers are provided which are partially immersed in the coating bath and the supports of which are also submerged in the latter. The strip-shaped material is guided around the deflector roller and then routed through the gap between the two coating rollers to the stripping nozzles. The deflector roller is placed below the coating rollers in the coating bath in this coating plant so that the strip-shaped material passes up through the space between the two coating rollers. Therefore, the strip is first carried by means of the deflector roller in a position from which it passes from the bottom upwards through the space between the two coating rollers. As the supports of the coating rollers and also of the deflector roller are submerged in the coating bath in this coating plant, they are subjected to high levels of wear taking into account not only the tension related to high friction or flow, but also thermal stress, and they have to be replaced frequently. However, its replacement causes the complete line to be immobilized and a considerable cost in terms of time, since the rollers must be lifted. This results in an interruption of the continuous operation and following the replacement, numerous stages of processing until the plant is returned to its working state. In addition, the strip to be coated can not move quickly without limitations in this known plant. An excessive amount of material is drawn out of the bath particularly at relatively high speeds, as the coating rolls are placed at a certain distance from each other. A large quantity of material must therefore be separated into strips by means of the stripping nozzles. In order to avoid the splashing phenomenon in the case of the coating baths where the strip is moving at a moderately high speed, it is known from J PA 55085664 to place the guide rollers through which the strip moves. which is to be coated on or under the surface of the coating bath, so that the distance between the surface of the coating bath and the point of contact between the strip to be coated and a roller is located within the diameter of the roller . This known plant also provides the regulation of the contact pressure force between the rollers and the intervening strip that is going to be coated, with the possibility of bending the latter, however, in this known plant, in addition to the deflector roll, in at least one guide roller is submerged in the contact bath so that its supports are located in the latter. Therefore, this arrangement causes the aforementioned wear phenomenon for the supports with the need to replace the corresponding rollers as long as they stop the plant. In comparison, an object of the invention is to provide a coating plant of the initially mentioned type whose movable parts have an extended life and to increase the speed of the strip to be coated. This object is solved by placing the supports of the coating rollers outside the coating bath. With this type of structure of the coating plant, in which the supports of the coating rollers are located outside the coating bath, the supports of these rollers are subject only to normal wear. In addition, the rollers and their supports can be accessed more easily from the outside, so that only a minimum amount of time is required to carry out a replacement if a support or a roller is defective. According to the supports of the coating rollers and therefore their axes are located outside the coating bath, very little coating material is displaced from the coating bath, as the space between the surface of the coating bath and the surface of the roller becomes smaller. it fills first with the coating material and only the adherent material is available for coating, without the presence of any additional material on the rollers. The claimed coating plant allows to achieve higher strip speeds. The coating material does not exhibit meniscus on the strip, since no matter! of coating that is present in excess on the rollers is transported away from the strip by the rollers. Advantages are obtained in particular by employing the annealing process subsequent to galvanizing taking into account the short immersion periods in the coating bath.

The rollers may be provided with a special coating in order to increase the service life of the coating rollers even when the supports are mounted outside the coating bath. The maintenance costs will also be substantially lower than in the case of the previous plant due to the aforementioned advantages. Advantageous developments are characterized by the dependent claims. The advantages are obtained with respect to the service life of the deflector roller bearings in a coating plant of the type described, in which the strip-shaped material is guided through the coating plant by means of one or more rollers. deflectors, if the supports of a baffle roller or all the baffle rollers are placed outside the coating bath. This arrangement of the deflector roller supports allows the coating material container to retain the coating bath to be substantially shallower than in the case of the previous coating plant, in which a deflector roller is always located below the rollers. of coating in the coating bath. This naturally applies to a plant structure that does not have deflecting rollers for the strip-shaped material to be coated, with the latter being fed directly to the coating rollers and deflected by one of these.

Only one baffle roller can be provided, this being located outside the coating bath. In this case, this roller works with minimum friction losses. If the deflector roller is located outside the coating bath or if the deflector roller is not provided, the coating bath container may also be particularly small. The coating rollers can advantageously move horizontally and vertically, so that the plant can adapt to different strip thicknesses being coated. Differential coatings can be achieved if the coating rollers are adjusted in distance from the strip material. The strip separation nozzles are preferably heated electrically. They can therefore be easily regulated. The use of a hopper effectively prevents oxidation of the coating, especially in the case of metal coatings, due to a closed atmosphere, for example due to N2. The viscosity of the coating can be maintained under a hopper, so that, together with the high temperatures of the strip separation means, the excess coating material can be reliably formed into strips. The speed of the strip to be coated can also be increased directly with high viscosities of the coating material. Temperatures of up to 600 ° C can be used for hot strip production of metallic materials. This results in significant advantages in the annealing process after the galvanization. Coating rolls of different diameters can be used, with larger roller diameters that are selected for high speeds to prevent the coating medium from splashing due to centrifugal forces. Variable strip speeds of 30 to at least 300 meters per minute can be achieved. Not only the coating rollers, but also the deflector roller if immersed in the coating bath, are preferably provided with strip separators which accumulate slag. The material in the form of a strip can be a metal strip, a strip of plastic material, a strip of fabric or a strip of paper. Different coating baths with coating temperatures of appropriate determinations are used accordingly. The coating material used can be, for example, zinc, aluminum, tin and alloys of a wide variety of types, and it is possible to use, for example, both liquids and coloring powder dissolved in water. The embodiments of the invention are described by way of example on the basis of the drawings, in which: Figure 1 is a section through a coating plant in which the supports of the deflector roller and the coating rollers are located on the coating bath, although the rollers are at least partially submerged in the coating bath. the coating bath. Figure 2 is a section through a coating plant in which the deflector roller and its supports are located outside the coating bath, while the coating rollers are partially submerged, with the supports of those rollers that are located on the coating bath. Figure 3 is a section through an oven nozzle nozzle of the coating plant according to Figs. 1 and 2 with the deflector roller mounted therein, and Figure 4 is a section through a coating plant having no deflector rolls and in which the strip-shaped material is guided directly around one of the rollers. of coating as it passes between the rollers. The coating plant according to Figure 1 is first described in terms of its basic structure, with additional details given in relation to the description. The coating plant comprises a container of coating material 1, which contains the coating bath 2 of the coating material. The coating material may consist of molten tin, zinc, aluminum or alloys of a wide variety of types or solvent dye in water. In the embodiment shown in accordance with Figure 1, the coating material container 1 is a coating tank containing the coating bath 2. A front coating roll 3 and a back coating roller 4 are immersed in the coating bath. coating so that the supports 5 and 6, respectively, are located on the upper bath level 7 of the coating bath 2. A deflector roller 8 is also immersed in the coating bath 2 in this embodiment. The supports 9 of that roller are also located on the upper bath level 7 of the coating bath 2.

The front and rear cover rollers 3 and 4 may or may not be driven. The coating rollers 3 and 4 are separated from one another by a small space, so that the strip 10 to be coated passes through the space to enter the subsequent coating roller, the usually is not driven. Both the front and rear coating roller 3 and 4 are positioned to be adjustable both vertically and horizontally. The coating plant can therefore be fixed to different strip thicknesses for coating in order to allow an optimum coating to be achieved. The strip 10 to be coated is guided from a preheating furnace 1 1 to the rear deflecting roller 8, rotated around it, conveyed to the back coating roller 4, through the space between the front and rear coating roller 3 and 4, respectively, and outside the coating bath. As already mentioned, the coating bath may consist of different liquids in order to provide the strip 10 with a cover. The bath can be at a temperature of up to 700 ° C. During the operation of a coating plant of this type the strip 10 to be coated is preheated in a preheating oven 1 1, immersed in the coating bath 2 and in the process rotated around the deflector roller 8 in the direction of the back coating roller 4, guided around this roller, through the space between the two coating rollers 3 and 4 and outside the coating bath. The back coating roller 4 can have a structured surface, for example, it can be profiled or approximate in order to obtain a uniform coating of the strip to be coated on that side. The two coating rollers 3 and 4 are placed in a minimum adjustable space one from the other. Regardless of whether or not it is driven, the front coating roll 3 tends to introduce coating material into the hollow space between the bath surface and the strip and its circumferential surface and thus produces a uniform coating on the strip that is going away. to coat on the side of the latter. Both sides of the strip 10 to be coated convey the excess coating material after it exits in the space between the coating rollers 3 and 4. The amount of coating material 2 entering is particularly small because the The shafts of the coating rolls 3 and 4 are located above the level of the bath 7 of the coating bath 2. The strip to be coated is covered by a thin layer of coating material on both sides and the consumption of the coating material is extremely high In order to obtain a coating that is as uniform as possible, the stripping nozzles 12 and 13 are provided on the covering rollers 3 and 4, respectively one on each side of the strip to be coated. However, a plurality of stripping nozzles can be placed one on top of the other on each side. The parts of the coating rollers 3 and 4 which are placed on the level of the upper bath of the melting bath, as well as the stripping nozzles 12 and 13, are placed in a hopper 14 in this mode. The hopper 14 allows the coating material to be separated into strips under improved conditions. The hopper 14 forms a space in which the formation of strips can be carried out in a closed atmosphere, which prevents the coating material from forming a lining or slag. The closed atmosphere can be, for example, an atmosphere of N2 or another gaseous atmosphere. The gaseous atmosphere, for example nitrogen or air, is supplied by the strip separation nozzles. The gaseous atmosphere can preferably be preheated in the stripping nozzles. Strip separation nozzles can be heated electrically, which provides the advantage of simple temperature regulation. The outlet temperatures of the separation gas in strips can be up to 600 ° C for the so-called strip separation in hot. Both the front and rear coating rolls 3 and 4 have a relatively large diameter in order to prevent the coating medium from splashing due to the centrifugal forces at relatively high strip speeds of, for example, 300 meters per minute. In order to remove the slag or excess coating materials that adhere to the coating rollers, the strip separators act on their outer circumferential surfaces. The outlet temperatures of the strip separation nozzles 12 and 13 are substantially higher than the ambient temperature to achieve advantageous strip separation. The two stripping nozzles 12 and 13 can be fixed to different wind jet resistances in order to allow strip separation to be varied if differences in coating thickness are to be achieved. Figure 2 represents another embodiment of a coating plant in which the deflector roller 8 is mounted at the outlet of the preheating furnace 1 1 so that not only its supports 9, but also the entire deflector roller is located outside the melting bath 2. However the deflector roller 8 is also located at the end of the preheat oven 1 1 in this mode. The strip 10 to be coated moves around the deflector roller and is immersed in the coating bath 2 on its way to the back coating roller 4. The coating operation is the same as the embodiment according to Fig. 1, and strip separation nozzles 12 and 13 are also provided according to the embodiment of Figure 2.

The coating plant according to Figures 1 and 2 has a compact structure, since the container of coating material 1 does not need to be very deep. The strip to be coated can move through the plant at high speeds. The front and rear cover rollers are not only adjustable horizontally and vertically, but their center axes can also be alternated to allow differential coating. Figure 3 shows how the outlet end of the preheating furnace 1 1 can be formed so that this part of the plant can be serviced and easily repaired. The deflector roller 8 is located under another hopper 17, which is mounted at the end of the furnace by means of a hinge.

The hopper 17 can be rotated if the deflector roller 8 is to be replaced or will be serviced. Figure 4 shows a coating plant that does not have baffle rollers and in which the strip to be coated is fed from the outlet of the preheating oven 1 1 directly to the adjacent coating roll 4, guided around it and between two coating rollers 3, 4.

Only the coating rollers 3 and 4 are provided with rotating parts, so that the number of parts subject to wear is kept to a minimum.

Claims (11)

REIVI N DICACIONES

1. Coating plant for coating a strip material with the coating material, in which the strip-shaped material to be coated is guided inside the coating bath, between two coating rolls, which are partially submerged in the coating bath, outside the coating bath and passing the separation nozzles in strips, in which the supports of the coating rollers (3, 4) are placed outside the coating bath (2).

2. A coating plant according to claim 1, in which the strip-shaped material is guided inside the coating bath by means of one or more deflecting rollers, in which the supports of a deflector roll (8). or of all the baffle rollers are placed outside the coating bath (2).

3. Coating plant according to claim 1, characterized in that one of the coating rollers (3, 4) is also a deflector roller.

4. Coating plant according to claim 1 or 2, characterized in that the or each deflector roller (8; ...) is partially submerged in the coating bath.

5. Coating plant according to claim 1 or 2, characterized in that only one baffle roller (8) is provided, this being located outside the coating bath (2).

6. Coating plant according to any one of claims 1 to 5, characterized in that the strip separators for the excess coating material act on the deflecting and coating rollers (8, 3, 4) submerged in the coating bath (2) .

7. Coating plant according to any one of the preceding claims, characterized in that the coating rollers (3, 4) and the deflecting roller or rollers (8; ...) can be adjusted to be parallel to each other in the direction horizontal or vertical.

8. Coating plant according to any one of the preceding claims, characterized in that the coating rollers (3, 4) are mounted to have an adjustable distance from the surface of the casting.

9. Coating plant in accordance with the claim 7 or 8, characterized in that the coating rollers (3, 4) can be adjusted in the vertical direction in order to adjust the amount of material entering.

10. Coating plant according to claim 8 or 9, characterized in that the front coating roller (3) is mounted pneumatically. 1. Coating plant according to any one of the preceding claims, characterized in that the deflecting roller or rollers (8; ...) can alternate in their vertical or horizontal position in a parallel manner in the vertical or horizontal direction.

11. Coating plant according to any one of the preceding claims, characterized in that two or more of the stripping nozzles (12, 13) are mounted one on top of the other on at least one side of the strip that is going to coat. 13. Coating plant according to any one of the preceding claims, characterized in that the stripping nozzles (12, 13) heat the strip means electrically. 14. Coating plant according to claim 13, characterized in that the air is used as the separation medium in strips. 15. Coating plant according to claim 13, characterized in that the nitrogen is used as the separating medium in strips. 16. Coating plant according to claim 14 or 15, characterized in that a hopper (14) is placed on the bath, under whose hopper the coating rollers (3, 4) and the stripping nozzles (12 and 13) are placed. 17. Coating plant according to any one of the preceding claims, characterized in that a hopper (17) is flexibly mounted by means of a hinge (18) at the outlet of the preheating oven. SUMMARY A coating plant for coating the strip material with coating material to be coated is guided inside a coating bath, and is guided between two coating rolls, which are partially submerged in the coating bath, outside the coating bath and passing the separation nozzles in strips, the supports of the coating rollers that are placed outside the coating bath. Preferably the strip-shaped material is guided into the coating bath by means of one or more deflecting rollers of which at least one is positioned outside the coating bath.