EP0098362A1 - Slot for applying foamed coating materials onto sheet-like materials - Google Patents

Abstract

1. An applicator device for applying foamed media on goods having large superficial areas, the device having a channel (22) which extends towards the application area and over the wording width, has consecutive upwardly and downwardly directed parts and terminates in an application slot (30), characterized by a controllable pressure pad (4) which is separated from the channel (22) by a diaphragm (40).

Description

Application device for applying foamed media to flat goods with an order channel or the like leading towards the order area.

The invention relates to an application device according to the preamble of claim 1.

Application devices according to the preamble of claim 1 are already known, which have a feed channel. However, the known design of such an application device does not always ensure that the foamed medium is constant and completely in constant motion. (U.S. Patent 3,969,780)

When applying foamed media, in particular foamed paint liquor, to a product, possibly a textile product that strongly absorbs the foamed medium, a relatively large volume is required as the application medium. This volume must be fed to the application level in such a way that it is ensured that the foam present in the application area has a consistently same quality.

The application of foamed media has the considerable advantage over the application of, for example, liquor that Relatively small amounts of liquor can be distributed evenly over a relatively large working width and that the supply of the liquor to the goods is easier to control in its foamed form due to its relatively large volume than is possible when applying viscous color pastes or relatively liquid liquors.

If the foaming of fleets brings considerable advantages over the conventional fleet order on a product, there are also considerable problems to be overcome.

Foam generally remains where it is placed. It does not move by itself, but has to be transported by some means. If foam remains in one place for a long time, it ages, releases the liquor and new, fresh foam is impaired in its consistency.

The present invention is therefore based on the object of creating an application system with which it is possible to supply large volumes of foamed fleet to an application area, which ensures that a very large amount of foamed fleet is available in a relatively short time, but on the other hand none There is a possibility that the foam will settle and age in any angular range. It must be ensured that the entire foam introduced into the system moves continuously and, if possible, continuously and that there are no different pressures across the entire working width.

This object is achieved by the features listed in the characterizing part of claim 1.

With the application device according to the invention, it is now possible to make a relatively large volume available in the channel for the application area, the channel serving on the one hand as a storage container, on the other hand as a feed space and due to its shape when the foam is continued, forcing it to do so, evenly the application area flow to.

Further advantageous embodiments of the subject matter of claim 1 are described in the subclaims.

The foam can be applied through a sieve or through a template. In the sieve area or in the template area, the foam essentially breaks down and is applied to the goods as a liquor. However, it is also possible to apply the foam directly to the substrate. The screens or stencils can be patterned or unpatterned. In screen printing machines or "screen printing" -like machines, it is particularly important to design the application device or the feed device to the application area according to the invention, since the patterning of the screen requires different volumes of liquor which are applied to the goods after the foam has been destroyed . The different consumption, for example from the edge area in relation to the middle area of the order, can thus be compensated for.

A wide variety of chemicals can be thought of as a foamed application medium. The first step is to apply paint, color pastes, color liquors for printing or dyeing. But it can also e.g. a latex foam can be applied as a layer. Other layers can also be applied if their chemicals can be foamed.

The goods or web can also be treated by the foam, e.g. can be washed by foamed equipment chemicals or also.

In particular, webs with a fibrous structure, such as textiles of all kinds, including e.g. also carpets, pile goods, such as velvet, also fleeces, but also felt. The application device can also be used with non-woven or paper, possibly also when printing or patterning plastics and the like. or when coating them.

Depending on the result to be achieved or the work step to be carried out, the foam is applied with more or less or controlled pressure.

Further characteristics and features result from the exemplary embodiments described below.

• Fig. 1 ein Ausführungsbeispiel der erfindungsgemäßen Auftragsvorrichtung, ausgebildet mit Doppelzuführung und einem unter steuerbarem Druck liegenden Druckpolster im^-Querschnitt,
• Fig. 2 ein Einbaubeispiel für die Auftragsvorrichtung im schematischen Querschnitt,
• Fig. 3 ein Ausführungsbeispiel der Auftragsvorrichtung ähnlich Fig. 1, jedoch ohne veränderbares Druckpolster oberhalb des Mittenraumes, jedoch mit eingebrachter Trennwand,
• Fig. 4 eine einseitige Zuführung.
• Fig. 5 ein weiteres Ausführungsbeispiel im Teilschnitt.

Some embodiments of the invention are explained with reference to FIGS. 1 to 5. Show it:

• Fig. 1 shows an embodiment of the application device according to the invention, formed with double supply and a controllable pressure lower than pressure pad in cross ^- section,
• 2 shows an installation example for the application device in schematic cross section,
• 3 shows an embodiment of the application device similar to FIG. 1, but without a changeable pressure cushion above the middle space, but with an inserted partition,
• Fig. 4 is a one-sided feed.
• Fig. 5 shows another embodiment in partial section.

As can be seen from FIG. 1, the application device 1 consists of two essential parts, namely the feed device 2 and a doctor body 3. A controllable pressure cushion 4 is provided in the upper area of the exemplary embodiment in FIG. 1.

In FIG. 1 there are two feed pipes 20 in the upper area of the feed device 2, which extend over the entire working width and in the exemplary embodiment shown are drawn from a side wall 21 to the second side wall (not shown). These feed pipes 20 are optionally with hose connections or the like. provided for the supply of a foamed medium from a foam generator 5. It is possible to provide a special foam feed for each feed pipe 20 and, if necessary, also a special foam generator. Such foam generators are known per se. They can be designed very differently, for example consist of a dispersion turbine for foam generation or be designed according to DE-PS 25 23 062.

A channel 22 is arranged below each of the feed pipes 20, each feed pipe 20 discharging the foamed liquor into its associated channel 22.

Each of these channels 22 is cascade-shaped and initially extends like a hairpin in the direction of the application level, rises after a turn and transfers the foam after it has passed a cascade wall 122 to a common center space 222, which tapers down towards the application area 6. Viewed in cross section, both channels 22 are mirror images of one another, just like the feed pipes 20.

The feed device 2 is built on an arbitrarily designed doctor body 3, which adapts to the inner surface of a screen cylinder 7 in the lower region. This screen cylinder can be patterned or non-patterned, made of wire mesh, it can also be a simple screen or a screen belt template. The doctor body 3 preferably has a through slot 30 in the center, but possibly also off-center, which can taper in the lower region and is continuously open towards the template or the screen cylinder 7.

Above the center space 222 there is a pressure cushion 4 which is under controllable pressure and which is separated from the center space 222 by a membrane 40. The pressure chamber housing 41 is provided with a pressure line 42 which is provided with a pressure measuring device 43 and an adjusting valve 44. The predetermined pressure that lies on the foamed medium in the central space 222 can thus be precisely preselected. Since the medium itself exerts a counter pressure, both pressure areas work together in a regulating manner. If the pressure drops in the area of the cascade-like channel 22, the membrane 40 expands and a constant pressure remains above the controllable pressure pad 4 in the application area.

• Zunächst erfolgt der Aufbau des Druckpolsters im Druckpolsterbereich 4 durch Einlasen von Luft oder einem anderen Druckmedium, bis ein Druck aufgebaut ist von beispielsweise 0,1 bar. Die Schaumzuführungsrohre bringen über eine nicht dargestellte Pumpe oder über den Schaumgenerator 5 Schaum in die Zuführungsvorrichtung 2, bis diese voll ist und durch Einbringen des Druckmediums bzw. des Schaums in die Zuführungsvorrichtung 2 baut sich hier beispielsweise ein Innendruck von o,12 atü auf, wobei dieser Druck über die bewegliche Membran 40 sich auch auf das veränderbare ggf. auch regelbare Druckpolster 4 auswirkt, das dann ebenfalls einen Druck von beispielsweise 0,12 bar od.dgl. hat. Ist der eingestellte Druck erreicht, wird das Einpiumpen des Schaumes herabgeregelt und die Vorrichtung ist arbeitsbereit. Der Druck im Innenraum der Zuführungsvorrichtung 2 baut sich ab durch Ausfließen des Schaumes bzw. Umwandlung des Schaumes in Flotte im .Auftragsbereich 6, beispielsweise bis auf etwa 0,1 bar, wobei durch an sich bekannte Mittel entweder der Schaumgenerator wieder beschleunigt-arbeitet oder die Schaumzuführung durch andere Vorrichtungen wieder vermehrt freigegeben wird, wodurch sich die Vorrichtung neu mit Schaum auffüllt. Daher ist ein ständiger, relativ gleichmäßiger Druck in der Auftragsvorrichtung 1, insbesondere der Zuführungsvorrichtung 2 vorhanden, so daß ein gleichmäßiger Ausfluß des Schaumes 'aus dem unteren Durchgangsschlitz 30 gewährleistet ist.

The device works as follows:

• First, the pressure cushion is built up in the pressure cushion area 4 by blowing in air or another pressure medium until a pressure of 0.1 bar, for example, is built up. The foam feed pipes bring foam into the feed device 2 via a pump (not shown) or via the foam generator 5 until it is full and by introducing the pressure medium or the foam into the feed device 2, for example, an internal pressure of o.12 atm builds up, whereby this pressure on the movable membrane 40 also on the changeable and also adjustable pressure pad 4, which then also has a pressure of 0.12 bar or the like, for example. Has. When the set pressure is reached, the inflow of the foam is reduced and the device is ready for use. The pressure in the interior of the feed device 2 is reduced by the foam flowing out or by converting the foam into liquor in the application area 6, for example up to about 0.1 bar, either by means of known means that the foam generator again accelerates or works Foam supply is increasingly released again by other devices, as a result of which the device is refilled with foam. Therefore, a constant, relatively uniform pressure is present in the application device 1, in particular the feed device 2, so that a uniform outflow of the foam 'from the lower through slot 30 is ensured.

Such an operation is known from DE-OS 23 00 289.

The cascade-like, mirror-image design of the channels 22 ensures that the central space 222 is always uniformly filled, and the tapering of the central space 222 towards the through slot 30 ensures a uniform inflow under slightly increasing pressure up to the application area 6.

The descending leg 22a of the channel 22 is narrower in the upper region than in the lower region, so that the foam supplied under pressure from the feed tube 22 has time to expand somewhat, and is then continued relatively evenly in the ascending branch, again with a slight opening of the clear space between the individual walls is possible, so that the ascending branch is slightly wider in the upper area than in the entrance area, which is below. The transitions are rounded, so that no corners can form under any circumstances in which foam could get stuck. This applies both to the outer area and to the inner area of the walls of the channels 22, which are made of sheet metal or plastic. These curves must merge without edges.

The design of the lower doctor body 3 can be chosen freely. A doctor blade is advantageous. This should adapt to the shape of the screen cylinder 7 and be designed in the manner of a slot doctor.

A mounting example of the device is shown in FIG. In this exemplary embodiment, the application device 1 has two feed pipes 20 with a number of connecting pieces 120 distributed over their length, which are connected to inlets 220 coming from outside. The overall device is thus a closed system or a closed double system.

The application device 1 is held by bearing rods 11 arranged on both sides. These can be adjustable and adjustable in height on the side bearing heads of a screen printing station or on a machine frame, which is not shown. These bearings are known for doctor blade arrangements and ink supply tubes.

The compressed air or another pressure medium is preferably fed to the pressure cushion 4 in the center.

The schematically indicated foaming device or a foam generator 5 has a compressed air feed 50 and a liquor feed 51 in a manner known per se. Both feeds are provided with control valves 52, 53.

3 essentially corresponds to the exemplary embodiment of FIG. 1, but no controllable pressure cushion 4 is provided in the upper region. After a rounding, cascade walls 122 in turn continue into the walls of the central area 222, which are diverging or more correctly converging in relation to one another in the media flow. All walls are preferably drawn from one side wall 21 to the opposite side wall, namely after

Possibility without seam or any heels.

The overflow area, which leads to the center space 222, is covered by curves 322 which open into a partition 422 and are brought together in this. The partition is inserted into the central space 222 until a narrowing of the cross sections a is still avoided. This partition serves to prevent the foam surfaces or foam streams coming from the right and left from colliding, which could result in a jam, but rather to channel them in the direction of the passage slot 30 in the doctor body 3.

4 shows an embodiment with only one-sided feeding. Here it is also possible to provide the doctor body 3 off-center with the through slot 30. In this exemplary embodiment, only one feed pipe 20 is provided and only one channel 22, but this is designed in exactly the same way as the channels of exemplary embodiments 1 and 3. Only the middle space 222 is not present, but a descending branch 222a, which opens into the upper region of the through slot 30 of the doctor body 3.

The lower curve 522 can correspond approximately to the size of the upper curve 322, the upper curve 322 generally being somewhat larger in radius than the lower curve 522.

Thus, not only do the clear widths of the channels 22 run in a hairpin shape to the central region 222 or to the descending branch 222a, but the walls also each run in a cascade or hairpin shape, specifically the inner walls of a hairpin shape and also the outer walls which then continue the inner walls.

There is still the possibility of providing nozzles in the doctor body 3, which is designed similar to a slot doctor, or other means of increasing the pressure build-up inside the device. This can also be done in that the through slot 30 tapers towards the bottom or towards the lower part or becomes narrower.

5 shows a further exemplary embodiment. In the upper area of the application device according to the invention there are again two feed pipes 20 arranged parallel to one another, which in turn traverse terminal side walls 21 or are closed by the side walls 21. Connection pieces 120 are in turn provided with inlets 220 which introduce the application medium into the tubes 20. The channels 22 are again cascaded in the form of wide slots with smooth side walls in an up and down shape, the deflections in the flow direction being covered by curves 322 and possibly narrowed. These curves each run together in partition walls 622, so that the guidance of the application medium is meandering.

In figure 5 a double system is shown, i.e. that two feed pipes 20 enter the foamed medium into the meandering slot through openings 320.

The entry is made in the upper region of a descending branch of the slot, that is to say downward and then ascending, then descending and ascending again, until the foam is introduced into the middle space 222.

The flow directions are shown in arrows.

The number of the respective diversions can be chosen arbitrarily.

The closed feed system is divisible in the middle and can be put together. This divisibility also makes cleaning easier.

The bearing rods 11, which are shown in FIG. 2, are in turn fastened to the side walls 21.

In the lower area it is shown that it is possible to mount the slotted squeegee foot or the squeegee body 3 on the feed device 2 by means of springs 32, the feed slot or the like, for example, by a soft membrane. has a shortening part 33 so that the squeegee body 3 can be sprung softly onto the fixedly mounted feed part 2. Rubber-elastic plates are incorporated as springs, which are located on both sides of the central space 222. The springs 32 can be made of rubber, plastic, spring plate or the like. consist. They can also be replaced by other types of spring elements, e.g. Springs arranged in rows, rubber buffers arranged in rows or the like.

Furthermore, the possibility is shown to provide spacers or guide plates 9 in the region of the channels 22. These ensure the distance between the side walls or cascade walls of the wide slot or wide channel serving as intermediate walls 622.

One has to take into account that such a device works for example over 5 m working width.

5 shows that the device can also be used in a somewhat smaller screen cylinder 7. In this case, the doctor body 3 could possibly be exchanged if the greater curvature of the smaller screen cylinder is to be taken into account.

It is essential that a device of bearing rods 11 or the like. is carried adjustable in height outside the sieve cylinder 7 and an application system is present in the working area or pulled across the working width, consisting of at least one channel 22 drawn over the working width in the form of a wide slot in a rising and going shape, which is in an order slot in one Number or in rows of order openings.

Of course, the idea of the invention is not limited to the exemplary embodiment shown. In the illustrated embodiment, e.g. 5, the cross sections are narrowed in each of the deflection areas. However, the other exemplary embodiments show that non-narrowed cross sections in the deflection areas are also conceivable and possible, although the narrowing of the deflection areas also increases the flow rate.

It is also possible, instead of the bearing rods 11, which are flanged to the side walls 21, to pull the feed pipes or at least one feed pipe 20 to the outside. However, this is only conceivable and possible for smaller working widths. In such a case, the feed pipes can possibly serve as bearing rods.

The advantage of the entire device in all of the exemplary embodiments is that the foam is not deposited anywhere. Not even a subset can stop anywhere. Even the smallest foam bubbles are constantly pushed forward by the flowing foam.

The constrictions present in each case result in a slowdown in flow technology and thus an equalization of the foam. First the foam is compressed and then it expands again.

The disclosed features can be used individually and in combination. which, insofar as they are new compared to the prior art, are regarded as essential to the invention.

Claims (10)

1, application device for applying foamed media to flat goods with an order channel leading in the direction of the order area or the like, characterized in that the channel (22) drawn over the working width is designed as a wide slot in an up and down shape and in one Order slot (30) .od. Like. flows. 2. Applicator according to claim 1, characterized in that the applicator consists of a feed device (2) with at least one channel (22) which carries in the lower region a doctor body (3), the shape of the inner surface of a preferably rotating template, a screen cylinder (7) or the like. is adapted and the order slot (30) or the like. wearing. 3. Application device according to claim 2, characterized in that the doctor body (3) is designed as a slot doctor with a continuous, tapering towards the application surface application slot (30). 4. Application device according to claim 1, characterized in that the channel formed as a slot (22) is guided in ascending and descending form over the entire working width and forms the connection between a feed pipe (20) for the application medium and the application or through slot (30) of a doctor body (3) _. and the feed pipe (20), preferably in the inlet area of a descending branch of the channel (22), extends over the entire inlet area. 5. The device according to claim 1, characterized in that two cascade-like channels (22) opposite each other are assigned to the application slot or through slot (30) of the application device and both cascade-like channels (22) merge into one another above the application or through slot (30) and form a common feed channel or central space (222) above the job area. 6. The device according to claim 1, characterized in that the center space (222) or the supply channel of only one channel in the upper region is provided with a variable adjustable or controllable pressure cushion (4). 7. Apparatus according to claim 1 and 3, characterized in that the through slot (30) or the application slot is tapered downwards or tapering downwards in the lower region. 8. The device according to claim 1, characterized in that the feed device (2) is designed as a closed system, preferably as a closed, two-sided feed system, such as a double system. 9. The device according to claim 1 and one of the following claims, characterized in that between the parallel or at an angle to each other walls of the channel (22) guide and spacer plates (9) are arranged which extend in the flow direction. 10. The device according to claim 1 and one of the following claims, characterized in that the device is supported by bearing rods (11) which are height-adjustable and adjustable mounted on the side bearing heads of a screen template or on a machine frame.

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