EP0930396A2 - Process and apparatus for applying a liquid or a pasty product onto a moving web - Google Patents

Abstract

For the direct or indirect application of a liquid or paste coating medium to the surface of a moving web (14), of paper or cardboard, deviations at the applicator (10) are corrected during the coating operation. One operating parameter is taken for the applicator (10) at the moving web (14), with a parameter measurement used which is taken shortly before detection of the deviation from the set parameter value. A correction to return the working to the required parameter level is applied momentarily, and repeated if necessary. The operating parameter, after its adjustment, is set back to the start value according to the establishment of at least the smallest deviations or independently of it. Or the operating parameter is returned to the start value after a given time lapse from the resetting. The coating quality on the web (14) is checked for faulty coating zones, to determine whether the number of faulty zones is acceptable or not. The coating on the web (14) is scanned visually by an operative, or optically by an optical scanner (86) for the measured scanning data to be evaluated for the presence of faulty coating zones. The optical scanner (86) registers the opacity of or the reflection from the coated web (14). The measured data are evaluated and displayed, for the operative to make a decision on any coating corrective action. The measured data are evaluated and processed pref. with a microprocessor (94), to inform the operative of the level of detected coating faults in relation to an acceptable count, and the action to be taken to correct at least one operating parameter. On detection of coating faults, the operative is given an optical and/or acoustic alarm warning. The microprocessor (94) can be connected to a control (100), which corrects at least one operating parameter to restore the web coating quality. The applicator (10) is a free jet system with a jet stream (16) of the coating medium delivered from the jet opening (12) to the web (14) surface in a direct coating application. For an indirect coating action, the coating medium is spread over a moving transfer surface to be transferred to the web (14). The parameter for correction of the coating quality, on a direct coating action, uses the jet stream characteristics and especially the shape of the jet stream. The parameter correction is applied by increasing the cross section of the jet opening (12), and then decreasing it. The increase in the jet opening (12) size is across the direction (18) of web (14) or transfer surface movement, locally where coating quality deviations have been registered, or the increase is over the whole jet opening length. An Independent claim is included for a web coating station with an applicator (10) to spread the coating medium over the web (14) surface. A monitor (86) registers the coating quality, and is linked to a microprocessor (94) to evaluate the measured data. The evaluation unit (94) is linked to an alarm system (96,98).

Description

The invention relates to an operating method for a device for direct or indirect application of a liquid to pasty application medium on a running web of material, especially paper or Cardboard, the material web with a Layer of the application medium is coated and the coating result then on deviations from a desired stroke result is examined, and if such deviations are found to correcting at least one operating parameter of the order work being affected.

In the paper manufacturing industry, coating or gluing of the raw paper webs application media in a layer thickness in the micrometer range applied. The order media is one Glue, a starch substance, a pigmentation medium or a correct one Coating color. It is very important that those applied to the paper web Layers a uniform line profile both in the transverse direction and in Longitudinal direction to that of the buyers of the paper manufacturers and the high quality requirements of the customer To meet paper. A variety of factors affect that Line thickness and the line quality of the applied layers. Therefore it is readily understandable that at the usual widths of the manufactured Paper webs of up to 10 m or more, usual machine speeds of up to 2000 m / min or more and accordingly voluminous Paper making machines encounter numerous disruptive factors that can negatively affect the stroke result. These include, for example temperature-related deformations of machine components, mechanical Wear of doctor elements, fluctuations in the consistency of the medium to be applied, contamination, etc. To avoid these interferences To get a grip on it, modern facilities for paper production are included a sophisticated sensor system provided at a variety of locations in the Production process Record measured values, based on which a Control center, usually a process computer, suitable actuators controlled via the individual operating parameters of the machine can be influenced. So it is common, for example, on the coated Material web the actual transverse profile of the applied layer by measurement to be recorded and in the event of irregularities in the dash cross profile Contact pressure and / or the angle of attack of a doctor element Adjust screws or hydraulic actuators.

All previous solutions to correct errors in the stroke result, i.e. of deviations from a desired stroke result is common, that one or more operating parameters in Dependency on detected errors gradually in the sense of a continuous reduction of errors can be adjusted like this long until the error in the stroke result is no longer observed. The river Oder the operating parameters then remain at their newly set values, until another error is observed that leads to further adjustments the or the operating parameters. This procedure is useful and corresponds to well-known principles of control engineering.

However, disruptive factors occasionally occur in the production process adverse effects on the bottom line result not by the continuous Readjustment of one or more operating parameters can be eliminated can. If there are dirt particles, clumps of the used Application medium, lint, dust particles or loosened from the paper web Pulp fibers in exposed areas in a commissioned work from a Lock the machine for paper production, for example in the nozzle gap of a free jet nozzle or on a doctor blade, the the resulting impairment of the stroke result is not without further by gradually adjusting the corresponding operating parameters Getting corrected. In particular, this is often not in a relatively short time possible, which is why with a large reject of unusable paper must be expected.

The invention is therefore based on the technical problem Procedure to specify that also with the disturbance factors mentioned above a quick correction of mistakes in the stroke result and thus one allows small rejects of unusable material.

To solve this problem, the invention proposes that to correct the deviations at least one operating parameter of the Order work with a running material web from a parameter base value the operating parameter before the deviations are determined possesses, briefly and if necessary repeatedly adjusted and then at least approximately reset to the parameter output value becomes.

In the solution according to the invention, a short-term counter to that corrective errors accepted significantly larger errors if the operating parameter is adjusted from its parameter output value is, this adjustment per se not to reduce the observed Deviations and approximation to a target state serves, but should only allow the elimination of the interference factor, so that at then resetting the operating parameter to the original value no fault points caused by such a disruptive factor Stroke result are more observable. Through sufficiently strong adjustment of suitable operating parameters, such as the contact pressure of a Doctor element, the flow pressure of the medium to be applied, the Cross section of an outlet opening for the application medium etc., can be achieved, for example, that dirt particles, lint or Clumps are washed away and the application medium again applied to the entire width of the material web without any problems becomes. This is due to the short-term adjustment of the operating parameter caused incorrect coating of the material web to a certain extent Committee. However, since this enables quick troubleshooting, this committee compared to such regular procedures low, where gradually an operating parameter in the sense of a Convergence to a target state is adjusted. As a temporary adjustment of the selected operating parameter can be, for example, an adjustment time of a few tenths of a second, but also viewed by a few seconds become. In the case of particularly stubborn soiling, a a correspondingly longer adjustment time may be required. In any case, the Operating parameters then again essentially on its Reset to the original value, what the inventive method of known correction methods. Because the correction of the deviations if the material web is running, no operational shutdown is necessary, that would massively increase production costs.

It is conceivable to reset the operating parameter to its Wait for the parameter output value until the desired one Has set stroke result. Accordingly, according to an embodiment of the operating method according to the invention provided that the operating parameters after its adjustment depending on the finding at least reduced deviations back to the parameter output value is deferred. It is then ensured that the cause of the discrepancies in the stroke result are completely eliminated.

Alternatively, it can be provided that the operating parameter according to its Adjustment at least reduced regardless of the finding Deviations are reset to the parameter output value. In particular, the operating parameter can be adjusted according to a predetermined time period is reset to the parameter output value become. In this case, it is not checked whether the adjustment of the Operating parameters has already led to the desired result before the operating parameter is reset. If necessary, the Adjustment of the operating parameter can be repeated if a single Adjusting does not have the desired success.

In a preferred embodiment of the operating method according to the invention It is envisaged that the Material web on the presence of order missing zones in the applied layer is examined in which application medium is not or was applied in insufficient quantities. Such order missing zones occur, for example, in the case of free jet commissions in the form of strips running along the running direction of the material web, if solid particles clog the jet nozzle of the free jet applicator locally. In these strip-like zones, there is almost no paint application the material web, which is why the length of the strips corresponding parts of the Material web are unusable and are treated as a committee have to. In addition, these strip-shaped order missing zones lead to that a doctor device downstream of the material web, about a squeegee blade, due to dry, unpainted surface becomes excessively hot, "burns up" locally, so to speak, and wears out more quickly. For this reason, there is a rapid streak detection in the coated material web very important.

There are various ways of examining the coated material web Approaches possible. For many strings, the order result detected by means of a sensor system that uses radioactive radiation sources, such as beta emitters. By means of such measuring arrangements small irregularities in the line profile can be measured become. In particular for strip detection, i.e. to capture strip-shaped longitudinal zones of the material web, in which no or only very little application medium has been applied to the invention Operating procedures, however, an optical examination of the Material web preferred. This optical examination can be done by one Operator to be carried out in the event of detection of Missing zones in the applied layer the adjustment and if desired, the subsequent deferral of the at least one Operating parameters causes. The visual capture more stripe-shaped Missed zones with the human eye is especially possible if the color of the substrate, i.e. the color of the raw material web, and distinguish the color of the medium to be applied for example if the color used is whiter than the backing paper is. Here it is also easily possible for an operator to Detect faulty coatings of the paper quickly with the naked eye and to take corrective action. But also when coating the material web with a color-like or almost colorless coating medium with accurate and careful observation, stripes in the line diagram also with can be recognized with the naked eye.

If the operator has found a faulty job, it can either adjust the at least one operating parameter cause manually in such a way that they are directly connected to mechanical Corrective intervention components, for example by turning an adjusting screw or opening and closing a wall of a jet nozzle closes. Often there will also be the possibility of one Monitoring and control center from individual operating parameters of the Commissioned work by pressing a button or adjusting sliding or To influence knobs, with a control unit, for example, in Form of a microprocessor then appropriate control signals to actuators of the commissioned work. For example, using actuators hydraulic actuators, the opening width of a nozzle gap Open jet order work can be changed locally and / or globally.

If the error detection is left to an operator, the Reject quantity of unusable material depends on how quickly the Operator notices the error and responds to it. It is decisive that is, the operator's attention in their work, which is caused by declining concentration can decrease, however, which is why up to Troubleshooting u. A significant amount of time may pass. For Relief of the staff, it is therefore expedient if the material web is examined by means of an optical measuring device whose measurement data then evaluated for the existence of order missing zones become. On the one hand, there have been suitable measuring principles Opacity measurement and on the other hand a reflection measurement on the coated material web exposed. As part of the opacity measurement, which can also be called a transparency investigation, it is determined how high the permeability of the coated material web for light is. It is easy to see that the light transmission the material web at the places where no or only very little application medium was applied, from the translucency the properly painted areas is different. The difference the opacity can be determined by means of a sensor arrangement of light-emitting transmitters on one side of the material web and light-detecting Receivers on the other side of the web measure. In the case of reflection measurement, this will be assumed that properly coated areas of the material web show a different reflection behavior for light than defects in the applied layer. In this case, the measuring device becomes a sensor system with light-emitting and light-detecting components on and include the same side of the web.

It can be provided that those provided by the measuring device Measurement data, if necessary after suitable processing, by a Display device displayed and then by an operator are evaluated, which in turn in the event of the detection of faulty zones in the applied layer the adjustment and if necessary the subsequent resetting of the at least one operating parameter causes. It is conceivable, for example, the won Measurement data in graphic form on a screen of a control center display. If an operator sees the one displayed on the screen The result of the measurement is interpreted in such a way that undesired order missing zones are present in the applied layer, it directs the necessary corrective measures, which in turn either in direct manual intervention on the mechanical components of the Commissioned work or in operations from the control center can exist. Although in this embodiment of the invention Operating procedures a relief of the staff from the tedious and error-prone examination of the coated material web with the naked eye and an increase in efficiency has already been achieved, however, the time to troubleshoot still depends on how carefully and conscientiously the displayed measurement result from the Operating personnel is interpreted and this reacts to it. A further ease of the operator's work and one step towards automation of the work processes can then consist of that the measurement data provided by the measuring device by a preferably microprocessor-based evaluation device on the The existence of order missing zones can be evaluated.

There is then the possibility that an evaluation result of the evaluation device an operator is notified and the operator in the event of detection of missed areas in the applied Layer the adjustment and, if desired, the subsequent deferral of the at least one operating parameter. It is conceivable for example, that in the event of the detection of missing orders in the applied layer to an optical and / or acoustic warning the operator is given. An operator who is continuously with the monitoring of the material web with regard to that The occurrence of streak-shaped error zones is then unnecessary. Rather, it is sufficient if one with other control tasks busy operator intervenes when they receive the warning perceives. Otherwise the automatic measurement and Evaluation run unattended, which is beneficial to personnel expenses and thus affects personnel costs.

Complete automation of error detection and troubleshooting can be achieved in that the evaluation device with a Control device is coupled, in the event of the detection of order fault zones in the applied layer the adjustment and subsequent ones The at least one operating parameter is reset. The control device implemented, for example, in the form of a central computer controls appropriate actuators, if necessary, through the influence be taken on the operating parameter or parameters to be adjusted can. The central computer can also be the evaluation device form, so that evaluation of the measurement data and implementation of the correction can be summarized in terms of hardware. The control loop thus formed enables automated error handling and troubleshooting that is quick and can be done reliably. This ensures the highest level of efficiency achieved, that in the case of order missing zones only very small Brings with it amounts of material scrap.

In a preferred embodiment of the invention it is provided that the commissioned work is designed as a free jet commissioned work in which Brush the application medium as a jet through a Beam outlet opening of the applicator through direct application the material web is directed and, in the case of an indirect order, to a current one Transfer surface is directed from which it then onto the material web is transferred, and that to correct the deviations at least one influencing the beam properties, in particular the beam shape Operating parameters is adjusted. As already mentioned, a such a free jet application work local blockage of the beam outlet opening result if dirt particles or clumps of the Application medium in the jet nozzle forming the jet outlet opening fix. To remove such a blockage, it is conceivable briefly increase the jet pressure to clear the constipation Push out the jet outlet opening. It is also conceivable, the beam to pulsate to release the blockage by pressure surges. It can also change the flow rate of the application medium briefly to have a detaching effect on the constipation achieve. In a preferred embodiment, on the other hand, that to correct the deviations, the opening cross-section of the beam outlet opening enlarged and then from its enlarged value from being reduced again. By enlarging the cross section Beam outlet can cause the blockage from continuing through the Application medium flowing out of the jet outlet opening be flushed out so that when the opening cross-section the beam exit opening then back to the original value is set, the conditions for an error-free job are restored are.

As a rule, it will be sufficient if to enlarge the opening cross-section the beam outlet opening its opening width - when viewed transverse to the running direction of the material web or the transfer surface - locally in Areas of deviations from the desired stroke result is enlarged. The prerequisite for this is that the jet outlet opening can be set locally in its opening side, for example with the help of set screws or by actuating hydraulic actuators. But it is also possible that to enlarge the opening cross section the beam outlet opening its opening width to essentially the total, transverse to the direction of travel of the material web or the transfer surface measured length of the beam outlet opening is increased. To can for example be a jet nozzle having the jet outlet opening briefly unfolded along its entire length and then again getting closed.

One especially for performing the above Operating method suitable device for direct or indirect Apply a liquid to pasty application medium on a running one Material web, in particular made of paper or cardboard, is said to be part of the Invention also enjoy independent protection. The device comprises in addition an application for coating the material web with a layer of the application medium, a measuring device for obtaining measurement data regarding the stroke result of the coated material web and a if desired, microprocessor-based evaluation device for Evaluation of the measurement data obtained for deviations from the measured Stroke result from a desired stroke result.

According to the invention, such a device provides: a) the Evaluation device is coupled to a control device which in the Case of discrepancy between the measured and the desired stroke result to correct it a short-term and if desired, repeated adjustment of at least one operating parameter of the order work with a running material web by one Parameter output value from the operating parameter before the determination which has deviations, and the subsequent deferral of the Operating parameters at least approximately back to the parameter output value causes, or / and b) the evaluation device with a Warning device is coupled, which in the case of the detection of Deviations between the measured and the desired Stroke result gives an optical and / or acoustic warning.

It is preferably provided that the measuring device at least partially as Optical measuring device is formed, which for metrological detection of the stroke result optical measurements on the coated material web carries out. The measuring device can measure Opacity properties and / or reflection properties of the coated Material web be formed.

The evaluation device for evaluating the measurement data is preferably on the presence of zones missing or insufficient applied application medium formed in the applied layer.

According to a preferred embodiment of the device according to the invention is the commissioned work as a free jet commissioned work with one Beam outlet opening for a direct application to the material web directed and, in the case of indirect orders, to a current transfer area directed beam of the application medium is formed. From this transfer area, expediently the outer surface of a transfer roller, that is Application medium can then be transferred to the material web, one Scraping off excess portions of the application medium and one Final dosing usually on the transfer surface before the transfer of the Apply medium to the material web.

When designing the commissioned work as a free jet commissioned work, it is recommended that the control device in the event of detection of deviations between the measured and the desired stroke result Adjustment of at least one of the beam properties, in particular the Beam shape, influencing operating parameters of the application works. In this case, the control device preferably brings about in the event of detection of deviations between the measured and the desired Stroke result the short-term enlargement of the opening cross-section of the Beam outlet opening. This can be done in such a way that the Control device in the event of discrepancy between the measured and the desired stroke result the short-term enlargement the opening width of the beam outlet opening - when viewed transverse to the direction of the material web or the transfer surface - locally in Areas of discrepancy between the measured and the desired stroke result. Alternatively, this can be provided be that the control device in the event of detection of deviations between the measured and the desired stroke result brief increase in the opening width of the jet outlet opening - at Viewing across the direction of the web or transfer surface - effected over their entire length.

The invention is illustrated below with reference to the single figure explained in more detail. In this figure, an embodiment of the is schematically Application device according to the invention with a free jet application unit shown. This free jet application is generally designated 10. There is a liquid or pasty medium, such as a coating color or a glue, in the free jet from an outlet 12 directly to one Material web 14 from. The beam is indicated at 16. He essentially goes over the entire width of the material web 14 transverse to its running direction (labeled 18) continuously through. The preferably from Paper, cardboard or cardboard existing material web 14 is in the area of Applicator unit 10 guided over a counter roller 20. It is from one roll of material, not shown, from which it is unwound, or from an upstream production station in which it is manufactured, fed, the material web 14 before or / and after the application work 10 if necessary, go through at least one further order station can, in the at least one further uniform layer of one to be applied Medium is applied to the material web 14. After this the material web 14 in the area of the applicator 10 by the Beam 16 formed veil of the medium to be applied and has been wetted with the medium, are connected in a downstream Doctor blade area 22 excess portions of the medium from the material web 14 doctored. For this purpose, in the embodiment shown, one on one Squeegee beam 24 held doctor blade 26 provided under a suitable blade angle and with a suitable contact pressure on the passing material web 14 is present. The contact pressure of the doctor blade 26 can be by means of one or more actuators 28 (here an adjusting screw) can be varied. In the doctor area 22, the previously applied in excess and only roughly pre-dosed medium the desired line width.

After passing through the doctor blade area 22, the coated material web 14 via guide deflecting rollers 30, 32 up into one not closer shown drying area in which the layer of applied Medium is dried, for example by means of infrared drying. The coated web of material 14 is then optionally further Processing stations fed.

The application unit 10 comprises an elongated support body 34 which in a housing 36 is housed. On the support body 34 is a Ink distribution pipe 38 held in the application medium from one side is pumped in. The color distribution pipe 38 points along it across Running direction 18 of the material web 14 measured a variety of lengths Ink passage openings 40 through which the application medium from the Paint distribution tube 38 enters a prechamber 42. Because of the pressure drop the medium to be applied along with the color distribution tube 38 such pressure is pumped into the paint manifold 38 that at the opposite A remaining amount of the application medium at the end of the color distribution tube 38 drains unused. This ensures that this too In the end there is a constant supply of fresh application medium and always fresh application medium through the color passage openings there flows with sufficient pressure into the prechamber 42.

From the antechamber 42, the application medium generally arrives at 44 designated jet nozzle, which has the jet outlet opening 12. The jet nozzle 44 is from a nozzle front wall 46 and from one Nozzle rear wall 48 limited. The nozzle rear wall 48 has in the area of Jet outlet opening 12 on a curved nozzle lip 50, which the Deflection of the jet 16 emerging from the jet nozzle 44 under one suitable angle to the material web 14 causes. Using one or more Actuators 52, the width of the jet nozzle 44 can be adjusted in specifically the distance between the nozzle lip 50 and the tip of the Nozzle front wall 46. This allows the jet cross section and thus adjust the amount of the emitted medium in the desired way. Expediently, they are distributed over the width of the material web 14 several actuators 52 are provided so that the width of the jet nozzle 44th can be set locally differently. For the actuators 52 come manually adjustable set screws or hydraulic or pneumatic actuable actuators in question. In the latter case, these are actuators to a pressure medium supply 54, indicated only schematically connected. For this purpose, a pressure line 56 is shown in dashed lines.

The nozzle front wall 46 is attached to a lever arm 58 which is around a Axis A is pivotally mounted on a bearing boss 60 of the housing 36 The bearing boss 60 has a stop lug 62, which one Stop projection 64 of the nozzle front wall 46 is opposite. In which In the operating state shown in the figure, the lever arm 58 is in its Operating position pivoted in which the nozzle front wall 46 with her Stop projection 64 on the stop lug 62 of the bearing projection 60 is present. The stop lug 62 thus creates a defined opening width the jet nozzle 44 is set by actuating the actuators 52nd can be finely adjusted.

At the end of the lever arm 58 remote from the nozzle front wall 46 one engages Piston rod 66 of a piston-cylinder unit 68 articulated to the Cylinder 70 by means of a fastening flange 72 on the housing 36 is held. The piston-cylinder unit 68 is via a pressure line 74 connected to the pressure medium supply 54. Another pressure line 76 extends from the pressure medium supply 54 to a pressure hose 78, which is arranged between the lever arm 58 and the housing 36. It is understood that the pressure lines 74, 76 may be pressure line bundles could be.

By actuating the piston-cylinder unit 68 in the sense that whose piston rod 66 is retracted into the cylinder 70, the Nozzle front wall 46 from nozzle rear wall 48 into an inoperative position be folded away in the jet nozzle 44 for cleaning or Maintenance work is accessible. To close the nozzle front wall 46 again close, the pressure hose 78 is pressurized so that the Nozzle front wall 46 about the axis A back into its operating position folds back.

A drain plate 80 attached to the doctor bar 24 and one on the Return channel 82 held by nozzle front wall 46 catches in the doctor area 22 scraped off excess medium and not guiding it preparation station for the application medium shown in more detail.

In the beam outlet opening 12 and an immediately preceding one the pre-chamber 42 adjoining ink inlet channel 84 can be Fix dirt particles or other solids so that in the area of these impurities, the jet 16 emerging from the jet nozzle 44 is more or less interrupted and the material web 14 is not or is not coated sufficiently. Provided this source of error for a while persists, it goes through in the line drawing of the applied layer Stripes noticeable, which can occasionally even be seen with the naked eye are. To detect such strips, the one shown in the figure Embodiment provided a measuring sensor 86, which the coated material web 14 before or after drying on the Existence of such strips is examined. The measurement sensor system 86 leads to this Reflection and / or opacity measurements on the coated material web 14 by what they are arranged on both sides of the material web 14, only by Has function blocks indicated optosensors. The sensor signals of the Measurement sensors 86 are connected to a control center via measurement signal lines 88, 90 92 delivered, the measurement signals in a function block in the Control center 92 evaluates schematically indicated evaluation logic 94. If the control center 92 striped zones missing order in the detected material web 14, it either directs appropriate Corrective actions or signals the result of their review optical or acoustic path to the operating personnel so that this initiates appropriate troubleshooting measures itself. For warning signaling the control center 92 can, for example, a warning lamp 96 or operate a buzzer 98.

The initiation of corrective actions or the warning signaling from one as a further functional block in the control center 92 schematically indicated control logic 100 causes that with the evaluation logic 94th is coupled. The evaluation logic 94 and the control logic 100 can be from a common process computer can be formed, but also as separate functional units can be formed.

To correct the faulty stripes on the material web 14 applied layer, the control center 92 causes a short-term Opening of the jet nozzle 44, i.e. a brief increase in the Beam exit opening 12. For this purpose, the control center 92 stands over a Control line (or a control line bundle) 102 with the pressure medium supply 54 in tax connection. When appropriate control signals are supplied to the pressure medium supply 54 is either the piston-cylinder unit 68 operated to open the nozzle front wall 46, or it are one or more of the pressure medium supply 54 Actuators 52 actuated to the opening width of the beam outlet opening 12th to enlarge. In the latter case there is in particular the possibility of one only local corrective action as it is possible and in itself is sufficient to operate only those actuators 52 in their area faulty stripes in the line of the applied layer were found were. By enlarging the beam outlet opening 12, the Streak-causing disturbance is flushed out of the jet nozzle 44 be, so that with subsequent restoration of the original Operating condition a perfect stroke result can be achieved. Algorithms can be implemented in the control center 92 according to which immediately after opening the nozzle front wall 46 or actuation the actuators 52 restored the original operating state regardless of whether there has been an improvement in the meantime Stroke result is observed. However, it is also possible that Restoration of the original operating condition depends on it make whether improvements in the stroke result have occurred, so that the period of time until the nozzle front wall 46 or the Actuators 52 can be correspondingly large. Especially with stubborn ones Impurities can be a repeated, repeated enlargement of the Beam outlet opening 12 by repeatedly opening and closing the Nozzle front wall 46 or repeated actuation of the actuators 52 to be necessary. The nozzle front wall 46 is closed again by increasing the pressure in the pressure hose 78. However, it is also conceivable an embodiment in which by means of the piston-cylinder unit 68 that Opening and closing the nozzle front wall 46 is possible.

Claims (29)

Operating method for a device for the direct or indirect application of a liquid to pasty application medium to a running material web (14), in particular made of paper or cardboard, an application unit (10) covering the material web (14) with a layer of the application medium and the coating result then it is examined for deviations from a desired stroke result, with at least one operating parameter of the application unit (10) being influenced in the event of the detection of such deviations in order to correct them,
characterized in that, to correct the deviations, at least one operating parameter of the application unit (10) with the material web (14) running is briefly and repeatedly adjusted from a parameter output value that the operating parameter has before the deviations were determined, and then at least approximately reset to the parameter output value becomes. Operating method according to claim 1,
characterized in that the operating parameter is reset to the parameter output value after its adjustment as a function of the detection of at least reduced deviations. Operating method according to claim 1,
characterized in that after its adjustment, the operating parameter is reset to the parameter output value independently of the detection of at least reduced deviations. Operating method according to claim 3,
characterized in that the operating parameter is reset to the parameter output value after its adjustment after a predetermined period of time. Operating method according to one of claims 1 to 4,
characterized in that, in order to examine the coating result, the material web (14) is examined for the presence of application defect zones in the applied layer, in which application medium was not applied or was applied only in insufficient quantity. Operating method according to claim 5,
characterized in that the material web (14) is examined optically. Operating method according to claim 6,
characterized in that the material web (14) is visually examined by an operator who, in the event of detection of missed areas in the applied layer, causes the adjustment and, if desired, the subsequent resetting of the at least one operating parameter. Operating method according to claim 6,
characterized in that the material web (14) is examined by means of an optical measuring device (86), the measured data of which are then evaluated for the presence of order error zones. Operating method according to claim 8,
characterized in that the measuring device (86) for examining the material web (14) carries out an opacity measurement on the coated material web (14). Operating method according to claim 8 or 9,
characterized in that the measuring device (86) for examining the material web (14) carries out a reflection measurement on the coated material web (14). Operating method according to one of claims 8 to 10,
characterized in that the measurement data provided by the measuring device (86), if desired after suitable processing, is displayed by a display device and then evaluated by an operator who, in the event of detection of faulty zones in the applied layer, the adjustment and, if desired, the subsequent resetting of the at least one operating parameter. Operating method according to one of claims 8 to 10,
characterized in that the measurement data provided by the measuring device (86) are evaluated by a preferably microprocessor-supported evaluation device (94) for the presence of order error zones. Operating method according to claim 12,
characterized in that an evaluation result of the evaluation device (94) is communicated to an operator and the operator effects the adjustment and, if desired, the subsequent resetting of the at least one operating parameter in the case of detection of missed areas in the applied layer. Operating method according to claim 13,
characterized in that in the event of detection of missed areas in the applied layer, an optical and / or acoustic warning is given to the operator. Operating method according to claim 12,
characterized in that the evaluation device (94) is coupled to a control device (100) which, in the event of detection of faulty areas in the applied layer, causes the adjustment and subsequent resetting of the at least one operating parameter. Operating method according to one of claims 1 to 15,
characterized in that the application unit (10) is designed as a free jet application unit, in which the application medium is applied as a jet (16) through a jet outlet opening (12) of the application unit (10) for direct application onto the material web in order to coat the material web (14) (14) is directed and, in the case of indirect application, is directed to a running transfer surface from which it is subsequently transferred to the material web (14), and that at least one operating parameter influencing the beam properties, in particular the beam shape, is adjusted to correct the deviations. Operating method according to claim 16,
characterized in that, in order to correct the deviations, the opening cross section of the beam outlet opening (12) is enlarged and then reduced again from its enlarged value. Operating method according to claim 17,
characterized in that, in order to enlarge the opening cross section of the jet outlet opening (12), its opening width - when viewed transversely to the direction of travel (18) of the material web (14) or the transfer surface - is locally increased in areas of deviations from the desired stroke result. Operating method according to claim 17,
characterized in that, in order to enlarge the opening cross section of the jet outlet opening (12), its opening width is increased to essentially the entire length of the jet outlet opening (12) measured transversely to the direction of travel (18) of the material web (14) or the transfer surface. Device for direct or indirect application of a liquid to pasty application medium to a running material web (14), in particular made of paper or cardboard an application unit (10) for coating the material web (14) with a layer of the application medium, a measuring device (86) for obtaining measurement data relating to the coating result of the coated material web (14) and if desired, a microprocessor-supported evaluation device (94) for evaluating the measurement data obtained for deviations of the measured stroke result from a desired stroke result,
in particular for carrying out the method according to one of claims 1 to 19,
characterized in that a) the evaluation device (94) is coupled to a control device (100) which, in the event of the detection of deviations between the measured and the desired coating result for their correction, a brief and if necessary repeated adjustment of at least one operating parameter of the application unit (10) while the material web is running (14) from a parameter output value that the operating parameter has before the deviations are ascertained, and the subsequent resetting of the operating parameter effects at least approximately again to the parameter output value,
or and b) the evaluation device (94) is coupled to a warning device (96, 98) which, in the event of the detection of deviations between the measured and the desired stroke result, emits an optical and / or acoustic warning. Device according to claim 20,
characterized in that the measuring device (86) is at least partially designed as an optical measuring device which carries out optical measurements on the coated material web (14) in order to record the coating result by measuring technology. Device according to claim 21,
characterized in that the measuring device (86) is designed to measure opacity properties of the coated material web (14). Device according to claim 21 or 22,
characterized in that the measuring device (86) is designed to measure reflection properties of the coated material web (14). Device according to one of claims 20 to 23,
characterized in that the evaluation device (94) is designed to evaluate the measurement data for the presence of zones of application medium which is missing or only applied in insufficient quantity in the applied layer. Device according to one of claims 20 to 24,
characterized in that the application unit (10) is designed as a free jet application unit with a jet outlet opening (12) for a jet (16) of the application medium directed onto the material web (14) when directly applied and directed onto a running transfer surface when indirectly applied, from which transfer area the application medium can be transferred to the material web (14). Apparatus according to claim 25 in connection with the feature
Group a) of claim 20, characterized in that the control device (100) effects the adjustment of at least one operating parameter of the application unit (10) influencing the beam properties, in particular the beam shape, in the event of the detection of deviations between the measured and the desired coating result. Device according to claim 26,
characterized in that the control device (100), in the event of the detection of deviations between the measured and the desired stroke result, causes the opening cross section of the jet outlet opening (12) to be briefly enlarged. Device according to claim 27,
characterized in that the control device (100) in the event of the detection of deviations between the measured and the desired coating result, the brief increase in the opening width of the jet outlet opening (12) - when viewed transversely to the running direction (18) of the material web (14) or the transfer surface - locally caused deviations between the measured and the desired stroke result. Device according to claim 27,
characterized in that the control device (100) in the event of the detection of deviations between the measured and the desired coating result, the brief increase in the opening width of the jet outlet opening (12) - when viewed transversely to the running direction (18) of the material web (14) or the transfer surface - effected over their entire length.

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