Applicator

Abstract

Application device in which a material web (5) encircles a roller (7) which is immersed in a liquid (1) in a trough (3), characterized in that the material web (5) passes through a metering gap (9) formed between a first roller (7) immersed in the liquid (1) and a second roller (10) immersed in the liquid (1), and that the first roller (7) is encircled by the material web (5) and the axis of rotation (8) of the first roller (7) is arranged below and the axis of rotation (11) of the second roller (10) is arranged above the liquid level (2).

Description

[0001] The invention relates to an application device in which a web of material encircles a roller that is immersed in a tub filled with a liquid.

[0002] Application devices for material webs are known and proven in a wide variety of designs. They serve to apply liquids to a material web, often as preparation for further surface finishing. The liquids to be applied are as diverse as the materials themselves, such as paper, films, or textiles; for example, aqueous solutions for impregnation or various resins for coating. The amount of liquid applied is determined by the passage of a material web through a metering gap. Such a gap can be formed, for example, by a doctor blade.

[0003] From DE 10 2009 034 605 B3, a device is known in which a web of material encircles a roller immersed in a trough filled with a liquid. Excess material is squeezed off between two calender rollers above the trough, between which the metering gap is formed.

[0004] Due to the design, the scraping or squeezing of excess liquid between two rollers occurs significantly above the tray. Consequently, a considerable amount of liquid flows back into the tray between the point where the liquid is applied to the web and the point of dosing. Liquid splashing off the web can also lead to significant contamination in the vicinity of the application device. Both of these issues are undesirable, as, for example, backflow of liquid can cause it to foam in the tray, resulting in a deteriorated application. Contaminants such as resins are difficult and costly to remove, and such contamination can also compromise the functionality of the device.

[0005] DE 199 19 234 A1 discloses a coating system with several coating rollers, wherein the bearings of the coating rollers are arranged outside the coating bath. DE 11 91 681 A further discloses a device with an immersed squeeze roller and separate wiper blades for a paper web.

[0006] CH 475 841 A describes a device for the continuous, simultaneous application of layers to both sides of a thermoplastic film web. Further coating systems are described in US 3 049 441 A, US 3 251 710 A, GB 1 448 259 A and US 4 444 814 A.

[0007] Against this background, the invention aims to provide an application device of the type mentioned at the outset in which contamination or backflow of liquids is largely avoided.

[0008] This technical problem is solved in an application device in which a web of material encircles a roller which is immersed in a liquid in a tub, according to the features of claim 1, in that the web of material passes through a metering gap formed between a first roller immersed in the liquid and a second roller immersed in the tub.

[0009] The liquid application is thus dosed directly above the liquid level, mostly still within the tub, so that excess liquid running off is unlikely to cause foaming or contamination from splashing.

[0010] In its design, the system further provides that the axis of rotation of at least one roller is adjustable horizontally and / or vertically, and that an adjustable drive is provided for at least one roller. The second roller can then be easily set in rotation, for example, by the friction that occurs. If both rollers have adjustable drives, counter-rotations are also possible.

[0011] These measures allow for easy adaptation to the material thickness of the web and the properties of the liquid.

[0012] Furthermore, the application device according to the invention is provided that the axis of rotation of a roller is arranged above the liquid level and that the metering gap is formed below the axis of rotation of this roller. Should any splashing of the liquid occur, such splashes are collected by the cylinder wall above the roller with the axis of rotation arranged above the liquid level.

[0013] It has proven advantageous if the metering gap is arranged at the level of the liquid level, whereby by possibly adjusting one of the rollers, the metering gap defined by the distance between the rollers can be slightly above or below the level of the liquid level.

[0014] In a further embodiment, which is not part of the invention, both axes of rotation of the rollers can be arranged above the liquid level. The metering gap is then formed above the liquid level, but excess liquid flows downwards between the two rollers when the material web is drawn off through the metering gap between the two rollers.

[0015] According to the invention, the axis of rotation of the first roller is arranged below and the axis of rotation of the second roller is arranged above the liquid level.

[0016] If, in particular, the axis of rotation of the first roller is arranged below the liquid level, its diameter will preferably be smaller than the diameter of the second roller. The diameters are preferably the same if the two axes of rotation of the rollers are arranged above the liquid level and lying in the same plane.

[0017] Regardless, the first roll is wrapped by the material web, and the second roll can also be wrapped by the material web.

[0018] The application device according to the invention is explained in more detail with reference to the drawing, in which only one exemplary embodiment and two non-inventional embodiments are shown schematically in side views, particularly with regard to the material thickness of the web being significantly exaggerated. The drawing shows: Fig. 1: a first embodiment, Fig. 2: a non-inventive embodiment and Fig. 3: another embodiment not in accordance with the invention.

[0019] All three figures show a tub 3 filled with a liquid 1 up to a liquid level 2.

[0020] For the application of liquid 1, the process passes through in Fig. 1. A material web 5 and a roller arrangement as shown by the arrow, of which one roller 6 serves only to guide the material web 5 against a first roller 7 above the liquid level 2, ensuring that the material web 5 is only wetted on one side when immersed in the liquid 1. In this embodiment, the axis of rotation 8 of the roller 7 is adjustable horizontally and vertically, as indicated by the double arrows. As a result of this measure, the distance between the roller 7 and a second roller 10, whose axis of rotation 11 is usually fixed above the liquid level 2, which defines a metering gap 9, can be adjusted.

[0021] In the example according to Fig. 2 A material web 15 encircles a roller 16, whose axis of rotation 17 is located above the liquid level 2. In the direction of rotation according to the arrow of the material web 15, a roller 18 with a smaller diameter follows the roller 16 and has a horizontally and vertically adjustable axis of rotation 19 below the liquid level 2. This allows the metering gap 20 between the two rollers 16 and 18 to be adjusted in the region of the liquid level 2 and adapted to the properties of both the liquid and the material web 15.

[0022] In the example according to Fig. In Figure 3, the axes of rotation 25, 26 of the two rollers 27, 28 of the same diameter are arranged at the same height above the liquid level 2. Only a horizontal adjustability of the axis of rotation 26 (shown here as an example by double arrow) is required to adjust the distance between the two rollers 27, 28 and thus the metering gap 29 for applying the liquid to the material web 30. Reference symbol list: 1 liquid 2. Liquid levels 3 tubs 5 Material track 6 rolls 7 roll 8 axis of rotation 9 Dosing gap 10 rolls 11 axis of rotation 15 Material track 16 rolls 17 axis of rotation 18 rolls 19 axis of rotation 20 Dosing gap 25 Rotary axis 26 axis of rotation 27 rolls 28 rolls 29 Dosing gap 30 material track

Claims

Application device in which a material web (5) encircles a roller (7) which is immersed in a liquid (1) in a trough (3), characterized in that the material web (5) passes through a metering gap (9) formed between a first roller (7) immersed in the liquid (1) and a second roller (10) immersed in the liquid (1), and that the first roller (7) is encircled by the material web (5) and the axis of rotation (8) of the first roller (7) is arranged below and the axis of rotation (11) of the second roller (10) is arranged above the liquid level (2). Application device according to claim 1, characterized in that the axis of rotation (8) of the first roller (7) is adjustable horizontally and / or vertically. Application device according to one or more of the preceding claims, characterized in that an adjustable drive of the first roller (7) is provided. Application device according to one or more of the preceding claims, characterized in that the metering gap (9) is arranged at the level of the liquid level (2). Application device according to one of the preceding claims, characterized in that the diameter of the first roller (7) is smaller than or equal to the diameter of the second roller (10). Application device according to one of the preceding claims, wherein the application device comprises a further roller (6) which is arranged such that the material web (5) is in contact with the first roller (7) above the liquid level (2), so that the material web (5) is only wetted on one side when immersed in the liquid (1).

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