EP1544353B1 - Curtain coater - Google Patents

Abstract

A curtain coating assembly (10) applies a coating of liquid or paste to one or both sides of a moving web of paper or carton. The liquid or paste is discharged from an overhead supply reservoir (18) to an intermediate holding reservoir (26). The holding reservoir discharges to a removable release unit (120). During the start-up process the removable release unit travels with the web from a first position to a second position while discharging.

Description

The invention relates to a machine for one-sided or two-sided application of a liquid or pasty application medium by means of at least one commissioned work on the surface of a moving material web, in particular made of paper or cardboard; in which the applicator dispenses the application medium from a dispensing opening arrangement, in particular a slot nozzle, directly or by mediation of at least one guide surface, in the form of a curtain or veil moving under the influence of gravity and / or under the influence of further forces towards a running background, wherein with direct application of the running surface is the surface of the web and, in the case of indirect application, the running substrate is the surface of a transfer element, preferably a transfer roller, which then transfers the application medium to the surface of the material web; wherein the machine in association with the commissioned work or a dispensing opening arrangement having dispensing part of the commissioned a medium collector, possibly a drip pan or gutter, for collecting issued from the discharge opening arrangement application medium in connection with the start and / or termination of the order and / or in Intercepting business interruption phases.

In order to ensure a good, high quality requirements sufficient order result, the various components of the mentioned machine are subject to a variety of requirements, including the medium catcher. In view of the fact that the curtain or veil does not have too high a height, that is, that the discharge opening arrangement is not too high above the running ground, the medium catcher should in particular be in Height direction be made comparatively compact. On the other hand, a proper discharge of the collected medium through the catcher to ensure what can be difficult especially for highly viscous media and / or very wide machines and height according to conventional conventional approaches possibly only at the cost of a large curtain height is possible.

The mentioned requirements are obviously in competition with each other. The problem may be somewhat alleviated by applying to a web portion which is rising or falling in the direction of travel, and that the application medium is at least initially removed in or against the web running direction. Nevertheless, the problem remains, the curtain or veil as low as possible on the running surface, in particular the material web surface, by the medium catcher and release again to avoid contraction of the released or cut curtain or at least reduce, so that the surface is not undefined with application medium, in particular application medium drops, is applied. It is an object of the invention to provide improvements here.

In a close contextual context with the problem addressed above, according to a second aspect of the invention, there is also the task of picking up the curtain or veil by a suitably designed edge for interrupting the application or releasing it to start the application, so that an undefined one also exists Loading the running surface, in particular the running web, is avoided with order medium. Thus, in the case of conventional medium collectors in the form of trays or gutters extending transversely across the material web (so-called "starting gutter"), the curtain can become adhesive on the wall of the starting gutter due to adhesion and upper-tension effects in the manner of the well-known "teapot effect" expires and from this undefined on the Subsurface drips. Such sagging of application medium on surface portions of the medium catcher should be avoided. The invention is also intended to provide improvements here.

In the case of machines of the type mentioned, it is generally necessary to clean components and surfaces which come into contact with the application medium. This is especially true for the medium catcher. Since such machines often have to meet tight space limitations in the direction and height direction, is especially in the field of usually provided "curtain nozzle" and the associated medium catcher little space available. It follows that the medium catcher is often difficult to access for cleaning purposes. Moreover, it is desirable if a quasi-automatic cleaning without immediate action by operators on the component to be cleaned is possible. The invention accordingly also has the aim of enabling effective cleaning of the medium catcher.

The DE-A-199 03 559 discloses a machine having the features of the preamble of claim 1 and a method of operating such a machine. The known machine is a paper machine with a curtain applicator, which is associated with a sliding drip tray to catch the curtain before or after application. The drip pan also has a receiving and release part, which is pivotable between two positions.

Further, the DE-A-198 23 686 a paper machine with a commissioned work, wherein a collecting tray for collecting application medium is arranged displaceably below the commissioned work. The drip pan of the known paper machine is equipped with a receiving and release part, which is attached as an inclined slide plate on a shaft and abuts a front stop the drip pan.

Against this background, it is an object of the present invention to develop a machine of the generic type so that the cleaning of the receiving and release part is facilitated with minimal loss of productivity of the machine.

To solve this problem, the invention provides a machine according to claim 1. In a machine according to the invention, it is provided that the medium catcher is equipped with at least one receiving and releasing part associated therewith, releasably attached or attachable thereto, the curtain being relative to the curtain at the start of applying the curtain together with the medium catcher or a subcomponent thereof or veil from a extending over the running ground edge or extending over the running surface edge for movement towards the running ground releases and / or which when interrupting or terminating the application by relative adjustment together with the medium catcher or one / of the sub-component the same to the curtain or veil with one / the extending over the running ground edge or with a / above the running edge extending into the curtain or veil occurs and at least initially receives this and keeps it from the current underground.

In the proposed manner, two inherently competing conditions can easily be met simultaneously. On the one hand, it can be achieved in such a way that the curtain is released as low as possible above the running substrate for starting the application or is taken up for interrupting or terminating the application. Local excess application as a result of a contracting by the surface tension curtain can be avoided or at least reduced. On the other hand, in a corresponding embodiment of the medium catcher or the subcomponent, a large application medium flow can still be collected, held and removed, for example, by providing a sufficiently high boundary wall for the receiving and release part. It can certainly provide that on the receiving and release part, the edge or edge opposite an upper edge of the boundary wall much lower over the current surface, in particular the material web can be arranged in the course of interaction with the curtain trapped application medium there simply remains and is not discharged to the medium catcher or its sub-component or to the web edge.

To solve the object of the invention, the invention further provides a method of operating a machine according to claim 2. It is proposed that before starting the application, the receiving and releasing part or at least one receiving and releasing part of several associated receiving and releasing parts attached to the medium catcher and / or that before starting the application or after the start of the order in the current Order operation, before the termination or interruption of the order from the Mediumaufänger the receiving or releasing a order medium holding or adhering application medium receiving and release part and the or at least one other, in particular cleaned or freed from application medium receiving and release part is attached to the medium catcher again. In particular, in this way remaining on the receiving and release part application medium can be easily removed.

According to one embodiment of the invention, it is provided that the medium catcher or the receiving and release part associated therewith has a flat, in particular blade-like, edge extending over the running ground, which in the direction of travel of the ground or in the direction opposite to the running direction to a extending current subsurface, preferably sharp-edged edge rising, which is used when starting the application to release the curtain or veil by relative adjustment to the curtain or veil to move towards the current surface or / and which when interrupting or terminating the order by relative adjustment to the curtain or veil in the curtain or veil to enter the curtain or veil. As a result of this design of the edge extending over the running substrate, it is avoided that when the application is interrupted, the curtain encounters a surface on which it could form droplets or that, when the curtain is released, it forms droplets forming on a surface due to the teapot effect , Ideal is a blade-like formation of the edge with a sharp edge.

It has proven particularly expedient if the edge extends at an angle of 20 ° to 60 °, preferably at an angle of 30 ° to 50 ° to the horizontal in or counter to the running direction. Furthermore, it has been found to be expedient if the edge extends over 5 to 50 mm, preferably over 10 to 30 mm in the horizontal direction.

Advantageously, the edge emanating from a substantially vertically extending wall portion of the medium catcher or a sub-component thereof or the receiving and release part. It has been found to be expedient if the wall section extends over 0 to 50 mm, preferably over 0 to 30 mm, most preferably over 10 to 20 mm in the vertical direction.

Advantageously, the wall portion or the edge emanating from a horizontally or inclined bottom portion of the medium catcher or a subcomponent thereof or the receiving and release part. It has been found to be expedient if the bottom portion is inclined at an angle of 0 ° to 50 °, preferably at an angle of 0 ° to 30 °, most preferably at an angle of 5 ° to 15 ° relative to the horizontal.

In a further embodiment of the invention, it is proposed that the medium catcher is assigned at least one supply line which is connected or connectable to a cleaning liquid supply and cleaning liquid can be supplied by the cleaning liquid supply via the surface sections of the medium catcher coming into contact with the collected application medium. The supply line may be an integral part of the medium catcher. For example, the supply line extends transversely to the running direction of the material web over the entire transverse dimension of the medium catcher. Particularly useful is an embodiment of the supply line as a spray tube.

The proposal of this embodiment may be surprising since, as is generally known, a recovery and, as a rule, after work-up, the reuse of the application medium collected by the medium catcher is provided. Such Recovery is difficult or impossible if cleaning liquid, such as water, enters the application medium return.

Nevertheless, in order to enable or at least facilitate the recovery of application medium, it is proposed that a valve arrangement is provided which is connected to at least one first connection on the medium receiver and is connected to at least one second connection to a cleaning fluid intake or cleaning fluid removal or purification fluid treatment or recovery arrangement, and is connected to at least a third port on a Auftragmediumaufbereitungs- or recovery arrangement, the valve assembly between a first valve state, in which the first is connected to the second terminal, and a second valve state, in which the first is connected to the third terminal, switchable is. In this way, one can dissipate collected application medium and used cleaning liquid separately and perform a respective re-use or disposal.

Also advantageous is a method for operating the machine according to the invention, in which before, during or after an order operation of the machine, the medium catcher is cleaned by supplying cleaning fluid via the supply line. with respect to the further developed machine, it is specifically proposed for the method that the valve arrangement for the cleaning is switched to the second valve state, and that the valve arrangement for collecting application medium through the medium catcher is switched to the third valve state. A particularly preferred embodiment of the method is characterized in that after starting the application, during the order operation, the medium catcher is cleaned by supplying cleaning fluid via the supply line.

Fig. 1

zeigt ein Beispiel einer Streichmaschine zum beidseitigen Auftragen auf eine Materialbahn aus Papier oder Karton.

Fig. 2

illustriert in den Teilfiguren 2a) und 2b) eine Möglichkeit für das Auffangen des Auftragsmediums durch einen verstellbaren Mediumauffänger im Zusammenhang mit dem Starten, Unterbrechen oder Beenden des Vorhang-Auftrags.

Fig. 3

zeigt eine weitere Möglichkeit für das Auffangen des Auftragsmediums durch einen verstellbaren Mediumauffänger im Zusammenhang mit dem Starten, Unterbrechen oder Beenden des Vorhang-Auftrags.

Fig. 4-7

zeigen erfdindungsgemäße Abwandlungen der Streichmaschine der Fig. 1 betreffend den Mediumauffänger und dessen Funktion beim Starten, Unterbrechen und Beenden des Vorhang-Auftrags und repräsentieren Ausführungsbeispiele erfindungsgemäßer Verfahren zum Betreiben von Streichmaschinen.

Fig. 8

zeigt ein weiteres Beispiel einer erfindungsgemäßen Streichmaschine.

Fig. 9

zeigt ein weiteres Beispiel einer erfindungsgemäßen Streichmaschine.

Fig. 10

zeigt einen bei den Beispielen der Figuren 1 bis 6, 8 und 9 erfindungsgemäß realisierten Vorhang-Abschneide- und Freigaberand des Mediumauffängers, Empfangsblechs bzw. Empfangs- und Freigabeteils, wobei sich Fig. 10 konkret auf die Ausführung des Auffangblechs des Mediumauffängers der Beispiele der Fig. 1 bis 3 bezieht.

Fig. 11

zeigt ein erfindungsgemäßes Empfangs- und Freigabeteil, das an einem wannenartigen oder rinnenartigen Mediumauffänger eingehängt ist und mit einem Vorhang-Abschneide- und Freigaberand entsprechend Fig. 10 ausgeführt ist.

Fig. 12

zeigt eine vorteilhafte Weiterbildung eines jeweiligen Mediumauffängers für Reinigungszwecke und repräsentiert ein weiteres Ausführungsbeispiel einer erfindungsgemäßen Streichmaschine.

The invention will be explained in more detail below with reference to embodiments shown in the figures.

Fig. 1

shows an example of a coating machine for two-sided application to a web of paper or cardboard.

Fig. 2

Illustrates in subfigures 2a) and 2b) a possibility for collecting the application medium by an adjustable medium catcher in connection with the start, interruption or termination of the curtain order.

Fig. 3

shows another possibility for collecting the coating medium by an adjustable medium catcher in connection with the start, interruption or termination of the curtain job.

Fig. 4-7

show erfistindungsgemäße modifications of the coating machine of Fig. 1 concerning the medium catcher and its function when starting, interrupting and ending the curtain application, and representing embodiments of methods according to the invention for operating coating machines.

Fig. 8

shows another example of a coating machine according to the invention.

Fig. 9

shows another example of a coating machine according to the invention.

Fig. 10

shows one in the examples of FIGS. 1 to 6 . 8 and 9 In accordance with the invention, the curtain cut-off and release edge of the medium catcher, receiving sheet or receiving and release piece, respectively, was realized Fig. 10 Specifically, on the execution of the collecting tray of the medium catcher of the examples of Fig. 1 to 3 refers.

Fig. 11

shows a receiving and release part according to the invention, which is mounted on a trough-like or channel-like medium catcher and with a curtain cut-off and release edge accordingly Fig. 10 is executed.

Fig. 12

shows an advantageous development of a respective medium catcher for cleaning purposes and represents a further embodiment of a coating machine according to the invention.

Fig. 1 schematically shows two curtain applicators 10-1 and 10-2 in a coating machine, which are used for direct curtain application on the two sides of a web of paper or cardboard 12. The guided over a plurality of pulleys 14 and 14 ', 16 and 18 guide assembly material web, according to Fig. 1 For example, from above to the guide roller 14 or - alternatively - fed from the right to the guide roller 14 '(dashed line) material web runs first below a curtain application head 18-1 of the first curtain applicator 10-1, for coating the first surface of the web. The curtain applicator head has in the usual way a distribution chamber running transversely to the running direction of the material web and a slot nozzle running in the same direction, which dispenses the curtain or veil from application medium, in particular coating color. The curtain or veil 24-1 strikes a sloping in the direction, with respect to the horizontal thus inclined portion 12-1 of the web 12, which is held by the guide rollers 14 or 16 or 14 'and 16.

When starting the coating machine or in the case of brief interruptions in operation, for example in the event of a web break, as well as in connection with the termination of the order of the Application medium curtain or veils collected by a movably mounted medium catcher 26-1, the in Fig. 1 is shown in a Auffangstellung in which he catches the curtain 24-1. The curtain is dashed but shown extended to the web portion 12-1 to show the order position. Fig. 2 shows the area of the curtain applicator 10-1 for both positions of the medium catcher 26-1, namely Fig. 2a ) the medium catcher 26-1 in the Auffangstellung accordingly Fig. 1 and in Fig. 2b ) the medium catcher 26-1 in an order position in which it is shifted relative to the catching position in the running direction of the material web, so that the curtain 24-1 strikes the inclined material web section 12-1.

The medium catcher 26-1 consists of a collecting plate 40-1 which extends over the entire width of the curtain in the direction transverse to the running direction of the material web and which extends substantially parallel to the inclined material web section 12-1, ie likewise inclined relative to the horizontal, and one itself adjoining this receiving and discharge chute 42-1, which extends in the transverse direction to the material web running direction and has a slope in this direction, in order to dissipate in the transverse direction the application medium fed from the collecting sheet her. The collected application medium is thus removed on the collecting tray 40-1 first in the running direction of the material web and then in the channel 42-1 in the transverse direction to the running direction. The receiving and discharge chute 42-1 is arranged next to a vertically extending material web section 12-2 or the web guide, which is held by the deflection rollers 16 and 18, essentially at the same height as the deflection roller 16, so that sufficient installation space is available in the height direction stands. It can therefore also be absorbed and removed large amounts of application medium, as may be necessary for very large web widths, for example, and it can also be provided a relatively large Abführgefälle in the transverse direction to the direction, as for example for highly viscous Application media, in particular coating colors, is required. Typical curtain colors for the curtain application have a viscosity of 50 to 500 mPs (= cP, centipoise) to give a guide value. In contrast, high-viscosity coating colors have a viscosity greater than 500 mPs (= cP, centipoise), again to give only a guideline value. The formation of the medium catcher corresponding to the medium catcher 26-1 is particularly well suited for high-viscosity coating colors or the medium catcher can be optimally designed for high-viscosity coating colors, namely with respect to the capacity of the receiving and Abführrinne 42-1, with respect to the slope of this channel in the transverse direction Running direction of the material web and with respect to the slope of the collecting plates 40-1 in the running direction of the material web.

Due to the deflection by the path deflection formed by the deflection rollers 16, 18, the other (second) material web side is now accessible from above for a medium application. The second curtain applicator 10-2 has similarly a curtain applicator head 18-2, which emits a curtain 24-2 to another, designated 12-3 material web section, which in turn is inclined relative to the horizontal and in the running direction of Material web drops. In turn, there is provided a medium catcher 26-2 which is disposed between a catching position in which the curtain 24-2 meets a catch tray 40-2 and is discharged via the catch tray and a take-up and discharge chute 42-2 and an order position the curtain hits the material web section 12-3, adjustable. The explanations and explanations concerning the catcher 26-1 apply with reference to FIG Fig. 2 in a similar way for the catcher 26-2.

As between the curtain applicators no intermediate drying, but only the web deflection is provided, which touchingly engages the second, not coated by the first curtain applicator 18-1 web surface, the web portion 12-3 before the application head 18-2 touching by the guide roller 18 and after the Curtain application head 18-2 held without contact by a Airturn 44, which belongs to the guide assembly and cooperates with another Airturn 46 to pass the web first through a first non-contact drying device 48 and then through a second non-contact drying device 50 therethrough. The drying devices 48 and 50 can be designed, for example, as infrared drying devices or hot-air drying devices.

In front of the application head 18-1 or 18-2, a device 19-1 or 19-2 can advantageously be provided for eliminating or weakening an air boundary layer entrained by the material web, for example a boundary layer extraction or a boundary layer scraper.

It should be noted that it is not mandatory that the medium catcher 40-1 or 40-2 be adjustable and the applicator head 18-1 or 18-2 is stationary. Fig. 3 FIG. 12 illustrates a modification of the coater in which the respective applicator head, in FIG Fig. 3 Specifically, the first application head 18-1 'is adjustable between a collection position in which the dispensed curtain on the collecting tray of the stationary medium catcher 26-1' ( Fig. 3a ), and an order position in which the curtain meets the downwardly sloping web portion 12-1 ( Fig. 3b ). The same can be provided for the curtain application head and the medium catcher of the second applicator 10-2.

It should also be noted that the Fig. 1 to 3 concerning the arrangement of the collecting tray of the medium catcher do not represent the optimal solution. The collecting tray of the medium catcher, or at least its running in the transverse direction to the direction of the web edge, which effectively cuts the curtain upon termination of the curtain application by adjusting the gun and / or the medium catcher and the curtain at the beginning of the order by correspondingly opposite adjustment of the gun or / and of Medium catcher releases the curtain so to speak, should - in deviation from the schematic representations in Fig. 1 to 3 - Be arranged as low as possible over the material web section to be coated.

In place of an adjustment of the entire medium catcher, advantageously only one adjustment of a receiving plate 41-1 "'of the medium catcher can be provided, as in FIG Fig. 4 illustrated. From the receiving plate 41-1 "', which is expedient itself as medium catcher beschzeichenbar (under designation of the component 26-1'" as a "drip tray" or the like) runs the captured application medium on the collecting tray 40-1 '"from and from this in the receiving and discharge chute 42-1 "'. The receiving sheet 41-1 "'may be designed with a specially designed cut-off edge for cutting or releasing the curtain in order to minimize accumulation areas on the application medium as a result of contraction of the curtain by the surface tension.

Other embodiments of the medium catcher are conceivable. Fig. 5 shows in the subfigures 5a) and 5b) a modification of the arrangement according to Fig. 4 , in which the receiving plate 41-1 is fixedly arranged on the collecting tray 40-1 and is adjustable together with the medium catcher 26-1 between a collecting position and an application position relative to the stationary application head 18-1. The receiving plate 41-1 may be removably attached to the medium catcher 26-1, and be removable from the medium catcher for cleaning purposes or for replacement as needed by an unpolluted receiving sheet. The receiving plate 41-1 may also be considered part of the medium catcher.

Fig. 6 shows in subfigure 6a) the possibility that the relative to the stationary medium catcher 26-1 '"adjustable receiving plate 40-1'" itself does not release the curtain or cuts, but is equipped with a separate receiving and release part 120, the detachable at the Receiving plate is arranged or will. The receiving and releasing part 120, which can be regarded as part of the medium catcher, is hung, for example, on a free edge or on a free edge of the receiving sheet. The receiving and release part is optimized to release the curtain when starting the application so or cut the curtain when finishing or interrupting the order so that an undefined loading of the material web with application medium is avoided or at least minimized. Thus, it can be ensured that the curtain cutting or releasing edge is arranged very low above the material web surface and that the curtain does not run off or wet on surface portions of the medium catcher when cutting or releasing, with the risk of undefined loading of the material web surface with application medium, for example with down dripping application medium. The design of the receiving and release part is such that the application medium solves properly when releasing an edge of the receiving and release part without running on the surface of the receiving and release part as a result of surface tension and adhesion effects "teapot effect"), and that when cutting the curtain this does not meet on flat surface portions of the receiving and release part.

To achieve these functions, it can be accepted that the receiving and release part receiving application medium, which is not deductible from the receiving and release part, but remains until a replacement or cleaning on the receiving and release part. As in Fig. 6a ) indicated by dashed lines, takes the receiving and release part in the collection position a position beyond the curtain, the curtain falls in the collection position so on the receiving plate 41-1 '"and runs on this on the collecting tray 40-1'" of the medium catcher 26th With an adjustment of the receiving plate 41-1 "between the order position, in which the curtain falls on the material web surface, and the collecting position, in which the curtain falls on the receiving sheet, that falls Order medium so only a short time on the receiving or release part 120, and the amount received by this order medium can remain on the receiving and release part 120. Based on a job cycle (starting the curtain application until the end of the curtain application), it is preferable to free the receiving and release part at the end of the cycle, so after recovery of the receiving plate 41-1 "'in the Auffangstellung of collecting medium, by removing and cleaning the receiving and release part from the receiving sheet, or replacing it with another receiving and releasing part without application medium.

Such a receiving and releasing part can also be located directly on the collecting tray 40-1 of the adjustable medium catcher 26-1 (FIG. Fig. 6 ) or stationary medium catcher order there to the same functions as in the example of Fig. 6a ).

Fig. 7 schematically shows a further embodiment possibility of the medium catcher. This points according to Fig. 7 a per se known, in cross-section spoon-like receiving and release part, which is pivoted relative to the collecting tray 40-1, on the one hand to record and release the curtain very low over the material web surface and on the other hand can be taken order application medium to the collecting tray 40-1 , This receiving and release part can be made interchangeable.

Once again referring to the embodiments of the Fig. 6 It should be pointed out that the detachably mounted or exchangeable receiving and releasing part shown there is particularly expedient when the medium catcher is designed with boundary walls rising high above the material web surface, as in FIG FIGS. 8 and 9 shown.

Fig. 8 schematically shows a curtain applicator 10 in a coating machine, the direct curtain application to a web 12 is made of paper or cardboard. The guided over a pulleys 14 and 16 comprehensive guide arrangement web 12 runs below a curtain applicator head 18 of the commissioned work. The curtain applicator head has in the usual way a distribution chamber 20 running transversely to the direction of travel of the material web and a slot nozzle 22 running in the same direction, which dispenses the curtain or veil 24 from application medium, in particular coating color. The curtain or veil 24 strikes a horizontally extending section 12 'of the material web 12.

When starting the coating machine or in the case of brief interruptions in operation, for example in the event of a web break, the coating medium curtain or curtain is collected by a movably mounted gutter 26, the in Fig. 8 is shown in solid lines in a Auffangstellung in which it catches the curtain 24, but optionally is mechanically adjustable in a job position in which they do not catch the curtain 24, so that the horizontally extending web portion 12 'is coated in the usual manner. In Fig. 8 is additionally dashed lines the collecting channel 26 shown in its order position.

In the usual way, the applicator can be preceded by a job pre-treatment device, for example a so-called air duct, air boundary layer scraper or air boundary layer suction, which is denoted by 19 and acts on the material web 12 in the region of the deflection roller 14.

In the embodiment according to Fig. 9 the medium catcher 26a is arranged stationary and integrated with the job pretreatment device 28a to form a structural unit. In order to be able to catch the application medium curtain 24 during startup of the coating machine or during brief interruptions in operation, the curtain application head 18a is located between an in Fig. 9 shown in solid lines collecting position in which the curtain is caught by the medium catcher 26 a, and one in Fig. 9 The order position shown by dashed lines is mechanically adjustable, in which the application head 18a is applied to a material web section 12 'rising in the direction of travel of the material web 12. The captured by the medium catcher application medium is - unlike the example of Fig. 8 - First not discharged in the transverse direction to the direction of the web, but counter to its direction in the direction of the arrow M, towards a symbolically shown fluid outlet 30 a or more corresponding fluid outlets.

If the receiving and releasing part 120 were not hooked on the medium catcher 26 or 26a, then the application medium would drain on the outer wall of the medium catcher when releasing the curtain to the web surface in the course of starting the application and cutting the curtain to complete the curtain job and drop uncontrollably onto the web surface. This is prevented by the special design of the receiving and release part with in the order position in the direction of the curtain obliquely projecting release and cutting edge. Moreover, this cutting and releasing edge is located significantly lower above the web surface than the upper edge of the media catcher so that, moreover, contraction of the released curtain due to surface tension to drips and the like is prevented or at least minimized.

The coating machines of the above examples each have a control unit (control unit 100 in FIG Fig. 1 ), which controls the coating process, especially when recording the coating or interrupting or finishing the coating. In particular, the control unit 100 activates an actuator arrangement which adjusts the respective application head 18-1 or 18-2 or 18a or / and the respective associated media catcher or its receiving sheet in order to start the application of the curtain for delivery to the surface of the material web to release or to stop the order to catch the curtain through the interceptor.

When starting the application, a stable curtain is preferably first set while it falls on the catcher. If a stable curtain is reached and the coating machine is otherwise in its desired state (desired running speed of the material web, operating temperature of the drying devices), the control unit then adjusts the medium catcher or its receiving sheet and / or the application head, so that the curtain subsequently strikes the material web surface ,

In a corresponding manner, the control unit interrupts or terminates the application by adjusting the medium catcher or its receiving plate and the respective applicator head in such a way relative to one another that the curtain is caught again by the catcher.

The collecting plates of the medium catcher according to the embodiments of the Fig. 1 to 3 , the receiving plate adjustable relative to the collecting tray according to the embodiment of Fig. 4 , The reception sheet releasably arranged receiving plate according to the embodiment of Fig. 5 and the receiving and release parts on the receiving sheet according to the embodiment of Fig. 6 or at the gutter according to the embodiments of the 8 and 9 are, as indicated in the figures, executed with a specially designed curtain cut-off and release edge 130. A particularly useful embodiment of the curtain cut-off and release edge is in the 10 and 11 better to recognize. Fig. 10 specifically shows the formation of the collecting tray 40-1 a medium catcher according to Fig. 1 and 2 with the curtain cut-off and release edge integrally provided thereon Fig. 11 specifically showing the example of a receiving and releasing part 120 having the curtain cut-off and release edge 130 integrally provided thereon. The receiving and release part is mounted on a medium catcher 26b, which is designed as a collecting trough or gutter with vertically upstanding walls 122.

The curtain cut-off and release edge consists at least of a cutting portion 132 which extends in the order position in the direction of the curtain rising and preferably ends in a sharp-edged cutting edge 134. Preferably, a flat, planar configuration of the cutting edge 132, wherein this preferably at an angle β of 30 to 50 ° relative to the horizontal in the direction of the curtain extends (in the order position) or in or against the running direction.

Preferably, the cutting edge 132 extends from a substantially vertically extending wall portion 136 of the curtain cut and release edge 130, which preferably extends vertically over a height of 0 to 30 mm, most preferably over a height of 10 to 20 mm ( Dimension y). The cutting edge 132 extends, starting from the wall section 136 or alternatively directly from the main section 138 of the collecting tray 40-1, preferably over 10 to 30 mm in the horizontal direction (dimension x).

The main portion 138 of the receiving plate 40-1 is preferably executed plan and may advantageously extend at an angle α of 0 ° to 30 °, preferably at an angle α of 5 to 15 ° relative to the horizontal, possibly parallel to the possibly rising or sloping material web.

The inclination of the cutting edge 132 and the distance between the cutting edge 134 and the wall portion 136 in the horizontal direction is such that the cut-off curtain does not run off the underside of the cutting edge 132 and not on the outer surface of the wall portion 136 comes. The curtain is trimmed at the completion of the application and cleanly released at the start of application without dripping media forming on the curtain cut-off and release edge which could drip onto the web. Dropping due to contraction of the released curtain is thereby avoided or at least reduced, that the cutting edge 134 may be arranged comparatively low above the material web surface, in any case lower than an upper edge of a trough-like medium catcher, which is designed for high capacity, such as Fig. 11 makes it clear

It is possible, according to another aspect of the invention, to carry out the medium catcher 26 or a respective medium catcher 26 of a coating machine with a cleaning arrangement for the quasi-automatic cleaning of the medium catcher. Fig. 12 shows a corresponding embodiment. The medium catcher 26 is designed with two spray pipes 140-1 and 140-2 which extend across the running direction of the web over the entire width of the medium catcher 26 and are connected via a valve 142 to a cleaning liquid supply 144, for example a simple water pipe. A sequence or the operations of the medium catcher, which are normally used for discharging the collected application medium (coating color) to a Auftragmediumaufbereitung 146 are connected in the embodiment via a switching valve 148 with a Reinigungsflüssigkeitsabführleitung 148 or the Auftragmediumaufbereitung 146, so that on the one hand the usually appropriate application medium Reprocessing and reuse possible and on the other hand, the cleaning liquid used to clean the medium catcher separately drained, for example, disposable or even a reprocessing can be fed. The cleaning of the medium catcher 26 by the cleaning liquid can advantageously take place during ongoing application operation, ie after the start of the application as a result of a relative adjustment between the application head 18 and the medium catcher 26. Fig. 12 shows in broken lines the possibility that a possibly provided receiving and release part 120 can be mounted on the arranged at the upper edge of the collecting plate 40 cleaning liquid supply line 140-2. For this purpose, the receiving and release part can be designed with passage recesses, which are the projecting from spray nozzles cleaning fluid let through. The receiving and releasing part may advantageously be designed with the curtain cutting and releasing edge according to the invention.

Claims (9)

1. Machine for the one-sided or two-sided application of a liquid or pasty application medium by means of at least one applicator (10) to the surface of a moving material web (12), in particular of paper or board;
   in which the applicator discharges the application medium from a discharge opening assembly, in particular a slot nozzle (22), directly or with the assistance of at least one guide surface, in the form of a curtain or film (24) moving towards a moving substrate under the influence of the force of gravity and/or under the influence of further forces, in the case of direct application the moving substrate being the surface of the material web (12) and in the case of indirect application the moving substrate being the surface of a transfer element, preferably a transfer roll, which then transfers the application medium to the surface of the material web;
   the machine having a medium collector (26), possibly a collecting trough or a collecting channel, associated with the applicator or a discharge part (18) of the applicator having the discharge opening arrangement, in order to collect application medium discharged from the discharge opening arrangement (22) in conjunction with the starting and/or ending of the application and/or in operation interruption phases;
   the medium collector (26-1"'; 26; 26a; 26b) being equipped with at least one receiving and releasing part (41-1"'; 120) assigned thereto which, when starting the application, releases the curtain or film, by means of relative displacement together with the medium collector or a partial component of the latter in relation to the curtain or film from an edge extending over the moving substrate or a sharp edge extending over the moving substrate, to move towards the moving substrate and/or, when interrupting or ending the application, by means of relative displacement together with the medium collector or a/the partial component of the same in relation to the curtain or film with a/the edge extending over the moving substrate or with a/the sharp edge extending over the moving substrate, enters the curtain or film and, at least initially, receives the latter and keeps it away from the moving substrate,
   characterized in that
   the receiving and releasing part (41-1"'; 120) is hooked in on one edge of the medium collector (26-1"'; 26; 26a; 26b) so that, for cleaning purposes or for replacement as needed by an unsoiled receiving and releasing part (41-1"'; 120), it is or can be attached detachably to the medium collector (26-1"'; 26; 26a; 26b).
2. Method for operating a machine for the one-sided or two-sided application of a liquid or pasty application medium by means of at least one applicator (10) to the surface of a moving material web (12), in particular of paper or board;
   in which the applicator discharges the application medium from a discharge opening assembly, in particular a slot nozzle (22), directly or with the assistance of at least one guide surface, in the form of a curtain or film (24) moving towards a moving substrate under the influence of the force of gravity and/or under the influence of further forces, in the case of direct application the moving substrate being the surface of the material web (12) and in the case of indirect application the moving substrate being the surface of a transfer element, preferably a transfer roll, which then transfers the application medium to the surface of the material web;
   the machine having a medium collector (26), possibly a collecting trough or a collecting channel, associated with the applicator or a discharge part (18) of the applicator having the discharge opening arrangement, in order to collect application medium discharged from the discharge opening arrangement (22) in conjunction with the starting and/or ending of the application and/or in operation interruption phases;
   the medium collector (26-1"'; 26; 26a; 26b) being equipped with at least one receiving and releasing part (41-1"'; 120) assigned thereto which, when starting the application, releases the curtain or film, by means of relative displacement together with the medium collector or a partial component of the latter in relation to the curtain or film from an edge extending over the moving substrate or a sharp edge extending over the moving substrate, to move towards the moving substrate and/or, when interrupting or ending the application, by means of relative displacement together with the medium collector or a/the partial component of the same in relation to the curtain or film with a/the edge extending over the moving substrate or with a/the sharp edge extending over the moving substrate, enters the curtain or film and, at least initially, receives the latter and keeps it away from the moving substrate,
   the receiving and releasing part (41-1"'; 120) being fitted or capable of being fitted detachably to the medium collector (26-1"'; 26; 26a; 26b), characterized in that
   before starting the application or after starting the application during running application operation, before ending or interrupting the application, a receiving and releasing part (120) holding application medium or having adhering application medium is removed from the medium collector and at least one other receiving and releasing part, in particular cleaned or freed of application medium, is fitted to the medium collector again.
3. Machine according to Claim 1, characterized in that the medium collector (26-1; 26-2; 26-1'; 26-1"'; or the receiving and releasing part assigned to the latter has an edge (132) which is flat, in particular like a cutting edge, extending over the moving substrate and which, in the running direction of the substrate or in the direction opposite to the running direction, runs so as to rise to a preferably sharp edge (134) which extends over the moving substrate and which is used, when starting the application, by means of relative adjustment in relation to the curtain or film, to release the curtain or film to move towards the moving substrate and/or, when interrupting or ending the application, by means of relative displacement in relation to the curtain or film, to enter the curtain or film.
4. Machine according to Claim 3, characterized in that the edge (132) extends at an angle (β) from 20° to 60°, preferably at an angle (β) from 30° to 50°, with respect to the horizontal in or counter to the running direction.
5. Machine according to Claim 3 or 4, characterized in that the edge (132) extends over 5 to 50 mm, preferably over 10 to 30 mm, in the horizontal direction (x).
6. Machine according to one of Claims 3 to 5, characterized in that the edge starts from a wall section (136) belonging to the medium collector and extending substantially vertically or from a partial component of the same or of the receiving and releasing part.
7. Machine according to Claim 6, characterized in that the wall section (136) extends over 0 to 50 mm, preferably over 0 to 30 mm, most preferably over 10 to 20 mm, in the vertical direction (y).
8. Machine according to one of Claims 3 to 7, characterized in that the wall section (136) or the edge starts from a bottom section (138) belonging to the medium collector and running horizontally or at an angle or from a partial component of the same or of the receiving and releasing part.
9. Machine according to Claim 8, characterized in that the bottom section (138) is inclined at an angle (α) from 0° to 50°, preferably at an angle (α) from 0° to 30°, most preferably at an angle (α) from 5° to 15°, with respect to the horizontal.

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