Coating apparatus – Solid applicator contacting work – Movably mounted applicator
Patent
1994-03-22
1995-10-03
Hastings, Karen M.
Coating apparatus
Solid applicator contacting work
Movably mounted applicator
152565, 1525651, 118104, 118118, 118216, 118248, 118261, 118313, 118410, 118413, 162281, B05C 500
Patent
active
054548705
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to a coating device for a paper web using an applicator roll, and particularly to means for applying a uniform coating layer onto the web on the backing roll. Such a coating device is known from EP 403845. In this connection, the applicator roll is frequently also referred to as a scoop roll, since the coating composition is, so to speak, scooped out of a reservoir and fed to the backup roll in the region of the application slot where the backup roll conducts the web of material to be coated, which generally consists of paper or cardboard. In this connection, only a predosing is effected in the applicator slot so that a doctor element is generally also provided later on on the same backup roll on the web of material in order to effect the final dosaging. The disadvantages of this device become particularly clear with high speeds of the web of more than about 800 meters per minute, so that said patent describes an improved arrangement which does away with the applicator roll. The problems which arise in this connection have, however, also not been completely solved as yet.
SUMMARY OF THE INVENTION
The object of the present invention is so to develop a coating device with which high speeds of the web of 1000 meters per minute and, in particular, more than 1200 meters per minute, are possible.
This object is achieved in accordance with the invention by a coating device has an applicator roll which forms an application slot with the backup roll which conducts the web of material around it. Adjoining the applicator slot is a space, which is formed at the outlet side of the application slot and between the applicator roll and the backup roll. Downstream of that space, there is a preferably flexible guide wall having a shape which approximates or is adapted to the surface of the backup roll and/or can be adapted thereto by the Coanda effect itself, which wall is spaced radially out from and forms a narrow slot along the web of material. The wall is at such a slight distance away from the web that the formation of drips or streaks in the applied coating, which might be caused by the centrifugal force, is excluded. The dosaging place for the final dosaging is formed by a dosaging doctor located past the end of the wall.
In this connection, the rapidly moving coating composition applied to the web is reduced or constricted to a given thickness between the web and the flexible wall by the difference in pressure. Furthermore, due to the Coanda effect, this layer of coating, despite the centrifugal speed which is acting upon it, remains as a uniform film on the web, from which layer the final layer thickness is formed when an excess amount of coating composition is scraped off also uniformly by the subsequent doctor element .
BRIEF DESCRIPTION OF THE DRAWING
The invention will be described below with reference to the sole figure of the drawing, which shows the device basically in a side view.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
In the figure, 1 is the applicator roll, 4 the backup roll, and C the web of material. A holder 13 for flexible wall element 2 is mounted here in the region of the axis of the applicator roll 1. The wall 2 has a free end downstream of its holder. In this connection, a space 8 is formed between the flexible wall 2, the applicator roll 1, and the backup roll 4 or web of material C, from which space excess coating composition can be fed back to the reservoir 16 or else to another reservoir. For the starting-up process, a spray nozzle 5 is provided which preferably sprays a liquid, which may also be the coating composition, into the space 8.
The coating composition therefore passes from the reservoir 16, conveyed on the surface of the applicator roll 1, to the application slot 10 over the space 8 another into the slot 7 which is formed between the flexible wall 2 and the backup roll 4 or web of material C. Here, the coating composition is reduced to a small or smaller thickness of film than in the applicator slot 10. The
REFERENCES:
patent: 3152918 (1964-10-01), Kraus
patent: 4185399 (1980-01-01), Gladish
patent: 4358481 (1982-11-01), Wallsten
patent: 4860686 (1989-08-01), Kato et al.
patent: 4903632 (1990-02-01), Sollinger
patent: 4920913 (1990-05-01), Knop et al.
patent: 5192591 (1993-03-01), Chance
Edwards Laura E.
Hastings Karen M.
J. M. Voith GmbH
LandOfFree
Coating device having an application slot formed between an appl does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Coating device having an application slot formed between an appl, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Coating device having an application slot formed between an appl will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1075009