EP1729889B1 - Device for painting and drying of endless materials - Google Patents

Description

The invention relates to a device for painting and drying continuous material, in particular wire, wherein a paint applicator for applying a paint layer to the continuous material and a drying device for drying the paint layer is provided on the continuous material, and a flow cooling device between the drying device and a return Deflection device for returning the continuous material to the paint applicator and a return cooling device between the return deflection device and a feed deflection device for feeding the continuous material to the paint applicator are arranged.

For many applications of electrical equipment electrical coils, especially with small dimensions are needed. For this purpose, insulated wires with very small diameters, preferably in a range of 0.05 to 0.5 mm are used. For the isolation of these wires special wire enamels are used with a solids content of preferably about 30% -40%.

Paint-coated wires are composed of a metallic core and a thin flexible coating shell. For the use of the painted wire, the lacquer layer must have both sufficient mechanical and electrical properties. For example, the wire and especially the paint layer is mechanically stressed when winding coils. Despite this stress, the lacquer layer must not lose its electrical insulation properties. Therefore, care must be taken when applying a faultless lacquer coating when painting wires.

The wire to be coated first passes through a paint bed in the paint applicator, which is supplied with a constant paint stream. Here, the wire is exposed to an excess of paint and it sets an undefined paint layer thickness. The thickness of this lacquer layer depends on various factors, such as the withdrawal speed and the surface tension of the paint. By means of nozzles or felts, the excess lacquer is then stripped off to achieve the desired wet lacquer thickness. As the life of Abstrezufilzenzen is low, instead metal nozzles are often used with carbide, sapphire or diamond inserts. The excess paint flows out of the nozzle on the inlet side and back into the storage tank. At the rear end of the wiper opening, the paint is pulled out of the nozzle by the moving wire.

Subsequently, the painted wire passes through a drying device, in which the painted wire is reheated and the solvents contained in the paint are evaporated. After this process, the solid particles of the paint form a solid insulating layer around the wire. The wire is then cooled again and fed again to the paint applicator. This process is repeated until the wire has been coated with the required entire lacquer layer. Depending on the machine and the product requirements, this process step must be completed up to 30 times. After the last pass, the wire is tested and wound on a spool in a winder.

The cooling of the wire between the individual painting or drying runs is provided in particular so as not to damage the paint surface by the subsequent deflections by means of the deflection devices and, moreover, during the paint application in the paint applicator not to evaporate too much solvent before it enters the drying device ,

So far, so-called. Combined cooling devices are known, which are arranged adjacent to the recirculation deflection device and in which the flow cooling device and the return cooling device are arranged directly above one another, so that the wire immediately after exiting the drying device in the flow cooling device is subsequently deflected by means of a return-deflection device, and then immediately re-enters the return-cooling device, from which it exits at the level of the arranged above the inlet opening in the flow cooling device again. The disadvantage here is that the wire again superficially heated after exiting the return cooling device, as a temperature compensation between the relatively hot wire core and the wire surface, ie the paint layer takes place. When entering the paint applicator this leads comparatively high surface temperature to undesired solvent evaporation. In order to keep the surface temperature at entry into the paint applicator thus low, therefore, the cooling capacity must be selected correspondingly high in known devices, so that the wire is cooled to the core. However, such a wire cooled down to the core is disadvantageous for the energy balance of the device, since the cold wire thus has to be reheated in the drying device. Further, the cooling efficiency of the return cooling device is lower than that of the flow cooling device, since the temperature difference between the cooling air (ambient temperature) and the continuous material is already very small.

From the DE 37 20 589 C1 For example, a Drahtlackiervorrichtung with a drying channel is known, to which only a flow cooling device connects.

In the DE 31 18 830 A1 a different type of wire-coating apparatus is shown in which a plurality of coating devices are connected in series one behind the other.

In the US 3 291 639 A a wire coating apparatus is shown in which the wire is first passed through a paint bath and then through a drying oven; However, flow and return cooling devices are not disclosed herein.

From the DE 16 52 395 A a device for enamelling wire is known, in which only a furnace is provided for evaporating the solvent.

Finally, it is still in the JP 11111085 A an oven with a subsequent cooling chamber disclosed.

The aim of the present invention is therefore to provide a device of the type mentioned, with which the above-mentioned disadvantages are prevented as possible, i. in particular a superficial heating of the continuous material before entry into the paint applicator is prevented.

This is achieved in the device of the type mentioned in that an outlet end of the return cooling device for the continuous material is arranged closer to the paint applicator as an inlet opening of the flow cooling device for the continuous material.

By providing a return cooling device whose outlet end is arranged for the continuous material in comparison to previously known cooling devices close to the applicator can a superficial heating of the continuous material can be prevented, so that when the continuous material enters the paint applicator undesired evaporation of the solvent due to the high surface temperature can be avoided. Thus, since superficial heating of the continuous material is reliably prevented, it is not necessary that the wire is cooled down to the core, which in turn allows the core temperature of the continuous material to be comparatively higher than in known devices, and thus in the drying apparatus a comparatively low energy input must be made, which has a positive effect on the energy balance of the entire device. Furthermore, the cooling capacity in the flow-cooling device can be specifically adapted to the process parameters, such as production speed, wire diameter, etc., so that a damage-free deflection at the return deflection device is achieved.

If a subsequent to the recirculation deflection arranged below the flow cooling device transport section, which preferably has a length of 4 m to 6 m, in particular of substantially 5 m, is designed to be exposed, a temperature compensation between a core of the continuous material and the Surface take place. This increases the cooling efficiency of the return cooling device, since the temperature difference between the surface of the continuous material and the cooling air taken from the environment becomes larger.

In order to determine the temperature of the continuous material as accurately as possible when entering the applicator and thus to avoid undesired evaporation of solvent as completely as possible, it is favorable if the outlet end of the return cooling device is arranged substantially immovably adjacent to the return deflection device.

If the return cooling device extends substantially the entire length of the drying device, the continuous material can be guided over a comparatively large distance in the return cooling device and thus in turn the cooling capacity of the return cooling device to the process parameters (production speeds, wire diameter, etc.). ) can be precisely adjusted so that surface cooling of the wire occurs to the extent that evaporation of the solvent in the paint applicator is avoided.

With regard to the most efficient cooling of the continuous material, the cooling air is blown counter to the direction of the endless material in the flow cooling device, it being favorable that the flow cooling device has at least one slot for passing the continuous material, which is connected to a suction fan and a pressure fan is. In this way, the cooling air can be introduced with the pressure fan counter to the direction of the endless material in the shaft and the heated cooling air are sucked by the suction fan.

With regard to a structurally simple and inexpensive embodiment of the device, it is advantageous if the return cooling device has at least one shaft for passing through the endless material, which is connected to the suction fan and preferably another pressure fan. Thus, with the suction fan of the flow cooling device at the same time the cooling air can be sucked through the shaft of the return cooling device against the direction of the endless material, with continuous material with a relatively large diameter of about> 0.8 mm and at relatively high production speeds of From about 600 m / min and another of the return cooling device associated pressure fan can be provided.

In order to be able to paint, dry and cool two continuous materials running parallel to one another at the same time, it is advantageous if the flow and return cooling devices have two shafts running parallel to one another.

• Fig. 1 eine Vorrichtung zum Lackieren und Trocknen von Draht mit einer Vorlauf-Kühlvorrichtung und einer sich im Wesentlichen unter der Trockenvorrichtung erstreckenden Rücklauf-Kühlvorrichtung;
• Fig. 2 eine perspektivische Ansicht der Vorrichtung gemäß Fig. 1 von unten;
• Fig. 3 eine weitere perspektivische Ansicht der Vorrichtung gemäß Figur 1 von unten; und
• Fig. 4 eine Detailansicht der Vorrichtung im Bereich der Eintrittsöffnung der Vorlauf-Kühlvorrichtung für den Draht.

The invention will be explained in more detail with reference to a preferred embodiment shown in the drawing, to which, however, it should not be limited. In detail, in the drawing:

• Fig. 1 a device for painting and drying wire with a flow cooling device and a return cooling device extending substantially below the drying device;
• Fig. 2 a perspective view of the device according to Fig. 1 from underneath;
• Fig. 3 a further perspective view of the device according to FIG. 1 from underneath; and
• Fig. 4 a detailed view of the device in the field of Inlet opening of the flow cooling device for the wire.

In the FIGS. 1 to 3 a device 1 for drying and painting of wires is shown, which has a paint applicator 2, a circulating air oven 3 as a drying device and a flow cooling device 4 and a return cooling device 5. The wire is here in the forward direction 6 through the oven 3 for drying the previously applied by the paint applicator 2 paint layer, then cooled in the flow cooling device 4 so that when deflecting the wire by means of a return deflection device 7 with pulleys 8 fresh applied lacquer layer is not damaged. After deflection with the return deflection device 7, the wire is returned in the return direction 9 to the paint applicator 2, wherein for deflecting the wire in the forward direction 6, a feed-deflection device 10 is provided with deflection rollers 8.

The wire is thus first coated with lacquer in the lacquer applicator 2, then solvent is evaporated in a circulating air oven 3 and the lacquer is polymerized. The wire provided with the lacquer layer is then introduced into the flow-cooling device 4 in order to cool the surface of the wire to such an extent that the lacquer layer, which is still plastic in the warm state, is not damaged during the deflection at the deflection device 7. In this case, the wire is cooled only to a temperature which is higher by approximately 50 ° C. than the maximum permissible surface temperature when it enters the paint applicator 2.

After deflection at the deflection rollers 8 of the return deflection device 7, the wire is then guided into an exposed transport section 11, in which a temperature compensation between the core and surface of the wire can take place. This increases the cooling efficiency of the recirculating cooling device 5 adjoining the exposed transport section 11, since the temperature difference between the surface of the wire and the cooling air is thus increased. The exposed transport section 11 has in the embodiment shown a length of about 5 m.

Subsequently, the wire enters the return cooling device 5, which extends below the circulating air oven 3 over a substantial portion of the length of the circulating air oven 3. An exit end 5 'of the return cooling device 5 is thus arranged relatively close to the applicator 2. In particular, the exit end 5 'of the return cooling device 5 is arranged closer than an inlet opening 4' of the flow cooling device, wherein in known return cooling devices, the inlet openings of the flow cooling device and the outlet ends of the return cooling device are arranged substantially in alignment in a plan view. By the cooling in the return cooling device 5, which extends over a considerable length of the furnace 3, in particular over the entire length of the furnace 3, thus the cooling performance of the return cooling device can be precisely adapted to the production conditions or process parameters, so that a surface cooling of the wire takes place to an extent in which evaporation of the solvent in the paint applicator 2 can be avoided. In the embodiment shown, a superficial cooling of the wire to about 70 ° C, the core temperature of the wire thus remains much higher than in known cooling devices, so that the energy balance of the entire device 1 is improved.

With regard to an efficient cooling of the wire, the cooling air with the aid of a radial pressure fan 12 is blown against the advance direction 6 of the wire in a shaft of the flow cooling device 4 and the heated cooling air sucked by a radial suction fan 13.

As in particular from Fig. 4 can be seen, with the suction fan 13, which is connected via an air passage 14 with the return-cooling device 5, and at the same time the cooling air against the return direction 9 sucked through the return-cooling device 5. For wires with a relatively large diameter of over 0.8 mm and high production speeds, ie wire throughput speeds from 600 m / min, the return cooling device may also have in the region of the outlet end 5 'connected to the return cooling device 5 pressure fan (not shown) , Furthermore are in Fig. 4 Still see supporting rollers 15 to reliably insert the wire in the return cooling device 5.

As in particular from the Figures 2 and 3 can be seen in the embodiment shown, the flow cooling device 4 and the return cooling device 5 each have two shafts and the deflection devices 7, 10 each have two pulleys 8, so that two wires can be painted in parallel. Of course, however, only a single shaft or a plurality of shafts may be provided. It is only essential that the outlet end 5 'of the return-cooling device is arranged relatively close to the applicator 2, so that a superficial cooling of the wire can be done precisely to the extent that evaporation of the solvent in the paint applicator 2 is avoided as possible.

Claims (8)

1. An arrangement (1) for enamelling and drying a continuous material, in particular wire, wherein an enamel applicator (2) is provided for applying a layer of enamel to the continuous material and a drying device (3) is provided for drying the enamel layer on the continuous material, and a forward cooling device (4) is arranged between the drying device (3) and a return deflection device (7) for returning the continuous material to the enamel applicator (2) as well as a return cooling device (5) is arranged between the return deflection device (7) and a feed deflection device (10) for feeding the continuous material to the enamel applicator (2), characterised in that the exit end (5') of the return cooling device (5) for the continuous material is arranged closer to the enamel applicator (2) than an inlet aperture (4') of the forward cooling device (4) for the continuous material.
2. The arrangement according to claim 1, characterised in that a transport section (11) following upon the return deflection device (10) and arranged below the forward cooling device (4) is configured to lie exposed.
3. The arrangement according to claim 2, characterised in that the transport section (11) has a length of from 4 m to 6 m.
4. The arrangement according to any one of claims 1 to 3, characterised in that the exit end (5') of the return cooling device (5) is arranged substantially immediately adjacent the return deflection device (10).
5. The arrangement according to any one of claims 1 to 4, characterised in that the return cooling device (5) extends substantially over the entire length of the drying device (3).
6. The arrangement according to any one of claims 1 to 5, characterised in that the forward cooling device (4) has at least one shaft for passing the continuous material therethrough, which shaft is connected to an exhauster (13) and a pusher fan (12).
7. The arrangement according to claim 6, characterised in that the return cooling device (5) comprises at least one shaft for passing the continuous material therethrough, which shaft is connected to the exhauster (13) and, preferably, to a further pusher fan.
8. The arrangement according to any one of claims 1 to 7, characterised in that the forward and the return cooling devices (4, 5) have two shafts extending in parallel to each other.

Images