DE102009029083A1 - Method for marking a material web section for controlling a fibrous web finishing plant - Google Patents

Abstract

The invention relates to a method for marking a material web section of a fibrous web, in particular a paper, tissue or cardboard web, which is produced endlessly in a fibrous material production plant and which is rolled up to form a winding roll (4). The method is characterized in that at least a partial area (B; B; B, ...) of the material web section is photographed in order to identify a material web section of the fibrous web.

Description

The invention relates to a method for marking a material web section for controlling a fibrous web finishing plant, in which a fibrous web, in particular paper, tissue or board web, with defects in the web, further processed or refined.

For the purposes of the invention, a fibrous web finishing plant is to be understood as meaning a slitter, a coater or a calender.

When winding up a fibrous web to form a winding roll or drum, the defective areas in the fibrous web which are detected and classified by the fault detection system or WIS (web inspection system) are usually rolled up as well. Within the paper machine there is no possibility to remove faulty web sections.

In order to find these faulty web sections in the rolled-up reel, the web is marked at the defects immediately after the WIS bar in the paper machine.

Defects in the fibrous web can be found or controlled again. This is necessary in the fibrous web finishing plant z. B. To avoid web breaks, relieve nips or adjust the speed. The marking must be clearly visible and positioned so that it does not interfere with further processing.

To mark defects, ink marking devices are typically used in papermaking. The ink marks are detected in the further processing of sensors or cameras, so that the subsequent process can be controlled accordingly.

However, the opening and closing of the inkjet nozzles takes some time, so that the entire printing process is relatively sluggish, it comes at web speeds of up to 2000 m / min and a printing time of 3 seconds to a mark extending over up to 100 m and therefore very inaccurate.

In addition, it comes due to the accumulated dust during the run of a paper web that the nozzle clogged or glued and must be cleaned up to twice a day. During the time of cleaning is usually no mark. The extremely expensive specialty ink also leads to very high operating costs.

Furthermore, the ink marks are usually distance information, which are usually worthless as soon as a part of the paper web has been lost or cut out, so that the length synchronization of the fibrous web is lost.

In particular, this marking method can only be used if the absorbency of the material is low, so that in particular tissue materials can not be marked.

task

The invention is therefore based on the object to provide a method by which a material web can be characterized without changing the material web properties, so that a fibrous web finishing plant can be controlled in such a way that web sections of a fibrous web in which the fibrous web has defects, from a web roll can be removed or further processed without the length synchronization of the fibrous web is lost, and improves process reliability and costs are reduced.

According to the invention this object is achieved by the method having the features of claim 1 and 7. The subclaims describe advantageous and particularly expedient embodiments of the invention.

Particularly advantageous may be characterized a fibrous web, if for the identification of a material web section, an endlessly produced in a pulp manufacturing plant fibrous web, in particular paper, tissue or board web, which is then rolled up to a winding roll, are photographed by this at least partial areas.

Preferably, the web is photographed at regular intervals, with a scheme is conceivable that adjusts the image distance to the web speed. Thus, at low web speeds short distances and at high speeds long distances can be selected.

The image file and the take-up length position of the photographed portions are stored together in a data memory. Just like the winding length position of the flaws found by the WIS. In addition, information about the type of error and the position of the error in the transverse direction (CD) can be stored.

For photographing the fibrous web is transilluminated, so that the structure of the fibrous web is visible. So it is possible to evaluate the recorded structure according to their material properties. The photos can thus be used to evaluate at least one material property and this material property can be assigned a code, which is then stored together with the winding length position.

Preferably, the photos are used to evaluate the formation, and / or dirt spots and / or fiber orientation.

For finishing, the finished spool is then unrolled and processed again in a fibrous web finishing plant.

According to the invention, the regulation of the fibrous web finishing plant takes place with the aid of the photographed subareas in that, when the fibrous web is unrolled, a camera at least temporarily takes up an image strip in which the subarea images were photographed. By matching with the recorded and stored images from the data memory, the absolute longitudinal position can be determined if two images match. With this length position and with the length position values of the defects from the memory, it is possible to calculate the distance to the next error position.

The camera can continuously record the image strip or it is controlled so that it only takes partial image strips and in those areas in which the sub-area images were photographed. The recording of partial image strips is to be used particularly effectively if an image position has already been found and z. B. for register control only the image positions must be adjusted, whereby the computational effort is reduced.

A further advantageous simplification is achieved in that the images of the image strips are used for evaluating at least one material property, and this material properties is assigned, at least in sections, at least one characteristic number which is used for matching with the stored characteristic numbers of the partial area images.

With the same index, it can be assumed that it is exactly the same subarea, since a subarea of a fibrous web is a kind of fingerprint. If several properties, such as the formation, and / or dirt spots and / or fiber orientation are defined for analysis by means of characteristic numbers, the uniqueness is further increased.

In order to avoid process faults at faulty fibrous web sites, the fibrous web finishing plant can be stopped to cut out the faulty fibrous web web sections, suspend the refining process and / or reduce the speed.

The fibrous web finishing plant may be, for example, a slitter, a coating unit for coating the web or a calender for smoothing the web.

• – die Faserstoffbahn bleibt unverändert
• – es ist jederzeit eine Längensynkronasition möglich auch wenn Teilbereiche abgeschwartet werden müssen
• – es fallen so gut wie keine Betriebskosten an
• – der Wartungsaufwand ist sehr gering

The particular advantages of the method according to the invention are:

• - The fibrous web remains unchanged
• - It is possible at any time a Längensynkronasition even if parts have to be waited
• - There are virtually no operating costs
• - The maintenance is very low

figure description

The solution according to the invention is explained below with reference to figures. The following is shown in detail:

1 a schematic representation of the paper machine with reeling and a plan view of the fibrous web

2 a schematic representation of a fibrous web finishing plant with unwinding and a plan view of the fibrous web

3 graphical representation of the fibrous web properties

1 shows a schematic representation of the paper machine 1 with reeling 6 and a plan view of the fibrous web 3 , The fibrous web 3 is in the paper machine 1 made and on the reel 6 rolled up into a drum.

Before rolling up the train goes through 3 the WIS system 2 , Seen in web direction before the WIS system 2 is also a camera 9 installed, with the sections of the fibrous web 3 in a strip area 10 can be photographed.

With the help of the WIS system 2 existing faults in the fibrous web are detected and stored their spatial position in MD and / or CD direction in a database.

The exact position of an error in the MD direction is calculated by calculating the rolled-up path length with the aid of z. B. the rotation angle measurement and the web thickness at the reeling 6 determined and stored together with the error in the database.

In parallel, the camera takes pictures 9 at regular time or spatially clocked intervals portions of the paper web 3 in the strip area 10 ,

The resulting images or image files of the subareas are evaluated according to specific properties, such as formation, dirt spots, fiber orientation, etc. During the evaluation, the determined properties are replaced by characteristic numbers according to specified criteria and stored in a data memory together with the longitudinal position data of the subregions.

The stored data may look like this, for example: Name of the picture Place in MD formation fiber orientation specks B1 0 m 1.1 0.5 0.1 B2 100 m 1.15 0.7 0 B3 200 m 0.9 0.1 0.2

By determining the paper properties and assigning characteristics to individual properties such as formation, fiber orientation and dirt spots, one obtains for each of the images a unique combination of properties, a type of DNA or fingerprint of the photographed fibrous web portion. The position of the image in MD direction is also determined by the rolled up web length.

Thus, one obtains an error database and a picture or attribute database which can be linked together so that it is possible to accurately determine the position of a MD-direction error between two pictures / sub-sections, once one has recovered at least one picture position on the web ,

2 shows a schematic representation of a fibrous web finishing plant 8th with unwinding 7 , as well as a plan view of the fibrous web 3 in the fiber processing plant 8th ,

Will the paper web 3 in the fiber processing plant 8th then for refining again from the unwinding 6 Unrolled, this is from a second camera 9a in the strip area 10 in which also the photographed sections are filmed.

The individual images of the film are continuously evaluated and provided with key figures and compared with the memory data of the image / property data memory.

When a known combination of the characteristic numbers or properties occurs, the absolute longitudinal direction position of the fibrous web is known, so that the distance to all other partial cutout positions and all error positions can be calculated therefrom.

Regulating the fiber processing plant ( 8th ), it is then only necessary to carry out a rolling length measurement and to control the process according to the errors present at fault positions.

By searching for the next known image, the next defect in relation to the image longitudinal position can be found clearly even after the scarfing. Or the register can be monitored by checking the subsections.

In 3 is shown graphically, how the evaluated pulp web properties change from image to image. Due to the infinite combination possibility, it is possible to unambiguously identify a subset (B ₁ , B ₂ , B _{3, ...} ).

LIST OF REFERENCE NUMBERS

1

Fibrous web making machine

2

Error detectors System

3

Fibrous web

4

Drum, winding roll

5

laser

6

retractor

7

unrolling

8th

Fibrous web coating line

9, 9a

camera

10

filmstrips

11

formation

12

fiber orientation

13

specks

B ₁ ; B ₂ ; B _{3, ...}

subregions

F ₁ ; F ₂ ; F _{3, ...}

error

Claims (14)

Method for marking a material web section of an endless in a pulp production plant ( 1 ) produced fibrous web, in particular paper, tissue or board web, to a winding roll ( 4 ) is rolled up, characterized in that for the identification of a web portion of the fibrous web at least a portion (B ₁ , B ₂ , B _{3, ...} ) of the web portion is photographed. A method according to claim 1, characterized in that the subregions (B ₁ , B ₂ , B _{3, ...} ) of the material web ( 3 ) are photographed at regular intervals and the image files are stored. Method according to one of the preceding claims, characterized in that the partial regions (B ₁ , B ₂ , B _{3, ...} ) of the material web ( 3 ) are photographed at distances adapted to the web speed and the image files are stored. Method according to one of the preceding claims, characterized in that the image files and the take-up length position (L _{B1, B2, B3, ...} ) of the photographed material web section are stored in association with one another. Method according to one of the preceding claims, characterized in that the photos for evaluating at least one material property ( 11 . 12 . 13 ) and these material properties ( 11 . 12 . 13 ) is assigned a code, which is stored together with the winding length position (L _{B1, B2, B3, ...} ). Method according to one of the preceding claims, characterized in that the photos for evaluating the formation ( 11 ), and / or dirt spots ( 12 ) and / or fiber orientation ( 13 ) be used. Method for controlling a fibrous web finishing plant ( 8th ) in which a winding roll characterized according to one of the preceding claims 1-6 is unrolled and finished, characterized in that during unrolling of the fibrous web ( 3 ) a camera ( 9a ) at least temporarily a video strip ( 10 ) and the images of the image strip ( 10 ) are matched with the stored subregion (B ₁ , B ₂ , B _{3, ...} ), from the data memory, and if they match the absolute longitudinal position (L _{B1, B2, B3, ...} ) and determined therefrom by means of Length positions (L _{F1, F2, F3, ...} ) of the defects (F ₁ , F ₂ , F _{3, ...} ), the distance to the next error (F ₁ , F ₂ , F _{3, ...} ) is calculated , Method according to claim 7, characterized in that the camera ( 9a ) continuously a picture strip ( 10 ). Method according to claim 7, characterized in that the camera ( 9a ) Partial image strip ( 10 ), in which the photographed partial area images (B ₁ , B ₂ , B _3,... ) lie. Method according to one of the preceding claims 7-9, characterized in that the image strips ( 10 ) for evaluating at least one material property ( 11 . 12 . 13 ) and these material properties ( 11 . 12 . 13 ) Is assigned to at least one code, which are used for matching with the stored key figures of the sub-area (B ₁ , B ₂ , B _{3, ...} ). Method according to one of the preceding claims 7-10, characterized in that the image strips ( 10 ) for the evaluation of the formation ( 11 ), and / or dirt spots ( 12 ) and / or fiber orientation ( 13 ) be used. Method according to one of the preceding claims 7-11, characterized in that the fibrous web finishing plant ( 8th ) for cutting out the defects (F ₁ , F ₂ , F _{3, ...} ) is stopped. Method according to one of the preceding claims 7-12, characterized in that the fibrous web finishing plant ( 8th ) at defects (F ₁ , F ₂ , F _{3, ...} ) suspends the refining process and / or the speed is reduced. Method according to one of the preceding claims 7-13, characterized in that the fibrous web ( 3 ) in the fibrous web finishing plant ( 8th ) is cut by means of a slitter, painted by means of a coating machine or smoothed by means of a calender.

Images