FI83734B - STRYKANORDNING. - Google Patents

Description

83734

SIVELYLAITE - STRYKANORDNING

The present invention relates to a brush device according to the preamble of claim 1.

One such coating device is known from U.S. Pat. No. 42,501,211. In the coating device according to the publication, the coating mass is fed in excess to a relatively narrow coating chamber formed at the web of material and forming part of the coating device. The wall or plate on the feed side of the material web forms a relatively narrow gap with the material web relative to the coating device, so that excess coating mass flowing out of the coating chamber forms a liquid seal, and the coating mass can be kept under pressure in the coating chamber. In this case, the residence time of the coating mass on the web of material is short, depending on the speed of the web of material, and preferably the excess coating mass is scraped off the web with an elastic squeegee on the discharge chamber discharge side, thus smoothing the coating. As a result of the short residence time of the brush mass, a relatively low coating weight can be achieved without the need for a high compression pressure of the brush blade. Prior art coating devices are also disclosed in FI 68098 and FI 72904, as well as in U.S. 3,301,214, 3,453,137 and 3,521,602.

; A One of the aims of this coating device is to distribute the coating mass evenly over the web so that::: the individual coatings do not separate. In addition, an absolutely uniform distribution of brush weight should be achieved.

This object is solved by the features according to the characterizing part of claim 1.

The shear forces present in the throttling gap achieve • · · *. namely, that the distribution of the coating mass on the web is: ': uniform.

In the following, the invention will be explained by means of exemplary embodiments I shown in the drawings, in which the figures show cross-sections of a coating device.

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The coating device 20 according to Fig. 1 is supported by a beam-like support 36 in which a coating composition chamber 32 is formed, from which the coating mass flows through a longitudinal, in particular slit-like opening 34 into the coating chamber 60 formed in the web. In this coating chamber 60 the coating mass is higher than atmospheric pressure. For this purpose, the coating chamber is limited or sealed in all directions. On the discharge side of the web there is a brush element 40 formed as a brush blade, which by its brush edges 46 removes excess coating mass from the web 26. On the feed side of the coating chamber 60 there is a throttle element , which forms a constricting gap 72 narrowing in the direction of travel of the web of material, in which the additional coating mass coming from the coating chamber 60 takes place. In this case, the pressure of the coating composition is further reduced from the pressure prevailing in the coating chamber 60.

Then the shear force F follows the formula F = n * v * A / l, where n is the viscosity of the coating mass, v is the web speed, A is twice the cutting surface 70 and 1 is the cross-sectional thickness of the choke gap 72.

Most preferably, the backing element of the web of material is a roll 22. The extension piece 44 of the beam 36 has a groove into which a pressure hose 42 is guided to mount the brush blade 40 to the front wall 28 of the coating chamber 32. A throttle plate 52 is attached to the rear wall 30 the brush blade 40 can be pressed against the web of material with variable compression pressure.

Most preferably, the length of the choke gap 72 is between 15-40 mm. The thickness of the throttling gap 72 is preferably between 5 and 15 mm, so that by applying an average of 1.5 liters of brush mass per machine width (cm) and time (min), a relatively streak-free brush pattern can be achieved. Since there is still a very strong flattening of the outflow of the coating mass through the throttling gap 70, in particular the relatively laminar flow of coating mass through the throttling gap, the air boundary layer formed on the web remains away from the throttling gap and thus from the coating chamber.

Figure 2 shows a variation in which the extension body 74 has an integral portion with a groove 76 to which the tip 56 of the throttle plate 52 engages. This coating body also has an upper surface 78 forming a choke gap 80. Fig. 3 shows a variation of a two-part coating body consisting of portions 82 and 84, the portion 82 extending into the coating chamber 60 as in other embodiments. leveling of the clay flow, which mass flow goes towards the brushing edge 46 of the brush blade 40. In this case, the possible turbulences are reduced or reduced. In this embodiment, the part 82 forms the cutting element in practice so as to form a throttling gap 88 by means of the upper surface 88.

Figure 4 shows another variation in which two coating devices forming a substantially mirror image with respect to each other are arranged on both sides of the upwardly moving web of material 10. Here, the coating pieces 94 are attached to the throttling plates 52, which form a constricting gap 96 which converges in the direction of travel of the web. The material web is supported by opposite throttling slots 96 like. The Theological behavior of the coating mass is also controlled in the same way here.

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In order to maintain the pressure of the brush mass in the coating chamber 60, in various embodiments, side seals are naturally necessary at both ends of the web of material or counter roll 22, however, side seals are not shown herein. Their shape can be found, for example, in DE publication 33 36 552.

Claims (3)

5,83734 A coating device for coating flowing webs of material, in which the coating device is formed with a coating chamber containing a coating mass delimited by a beam-like counter-guide element extending transversely to the material web as well as the rake element held by the support piece on the discharge side of the coating chamber and the throttling plate for the coating mass leaving the coating chamber against the direction of travel of the material web on the feed chamber. a fitting extension piece extending so far into the coating chamber (60) that a coating mass flowing to the coating edge of the squeegee element (40) is achieved laminar flow. Device according to Claim 1, characterized in that the throttling gap (72, 80) has a length of at least 20 mm. Device according to Claim 1 or 2, characterized in that the constriction gap gradually decreases in the direction of travel of the web of material, i.e. towards the coating chamber. 6 83734