EP1541762A1 - Method and apparatus for controlling at least one process-related property during manufacturing of a fibrous web - Google Patents

Abstract

Following a papermaking process one or more mechanical parameters are monitored at two different points astride the discharging web. The parameters measured are e.g. linear forces (F) or an equivalent dimension, squeeze force or web tension. The parameters measures at one point are used as a corrective feedback regulation value at an upstream work station. Further processes measured may include winding harness, web tension at individual winding stations, smoothness, thickness, modulus of elasticity, density per unit area, thickness etc. Also claimed is a commensurate assembly.

Description

The invention relates to a method for controlling at least one process-relevant Property during the production of a fibrous web, in particular a paper or board web, with a production machine, in particular a at least one headbox, a wire section, a press section, a Drying section and a paper or board machine having a winding machine.

From the prior art, it is well known that a fibrous web for Monitoring their manufacturing process with the help of one or more known Scanning frame is scanned. In this way, information about the basis weight, the thickness and the humidity of the fibrous web to be produced won.

In the German patent application DE 199 20 133 A1 (PR10894 DE) of the applicant discloses a method and apparatus for measuring line force (Nipkraft), which occurs in the winding nip between two rotating rolls reveals. In this case, the line force by means of at least one at least one measured the two rotating rollers mounted piezo elements. Further this disclosure describes various arrangement possibilities of Piezo elements on at least one of the two rotating rollers. The different Arrangement possibilities and the high measuring accuracy of the piezo elements allow accurate measurement of line force.

It is therefore an object of the invention to provide a method of the type mentioned to improve that there is an additional possibility of regulation at least a process-relevant property of the production process of the fibrous web to achieve a high quality of the finished fibrous web and to ensure. Furthermore, should at least one device for Implementation of the method according to the invention can be specified.

The object is according to the invention in the mentioned method by determination at least one local change and / or at least one local difference at least one first characteristic transverse profile of the fibrous web by measuring at least one mechanical parameter of the fibrous web at least two points distributed over the width of the fibrous web and points by influencing the at least one first characteristic transverse profile on the at least one position depending on the local change or the local one Difference by changing at least a second property cross profile the fibrous web dissolved at least one further location, wherein the at least a first property profile is the line force or an equivalent Size, in particular the pressure, and / or the web tension or an equivalent Size is.

By influencing or regulating the at least one second Property can be the at least one first property, so the line force or an equivalent size, in particular the pressure, and / or the web tension or an equivalent size, and thus the process-relevant property preferably be controlled as desired to a desired value.

The values obtained by the method according to the invention for the line force and / or web train thus serve as control variables for the process of production the fibrous web to ensure the highest possible quality of the finished fibrous web to obtain the finished fibrous web along its width as possible should have uniform thickness and as uniform as possible modulus of elasticity. Thus, the method according to the invention provides a further possibility for monitoring ready for the production process of the fibrous web.

The inventive method also has the advantage that it has a requires considerably less mechanical effort than that of the prior Technique known methods. Besides, it can be in addition to the already known ones Methods are used. This will increase the accuracy of the Monitoring of the production process of the fibrous web increased.

The process-relevant property during the production of the fibrous web comprises in a preferred embodiment at least the winding hardness (radial stress), the tension in the individual layers of the winding roll and / or the Smoothness grade of a smoothing process, if this process step in the manufacturing process the fibrous web is provided.

The at least one second property transverse profile of the fibrous web comprises in Advantageous embodiment, at least the thickness and / or at least one modulus of elasticity, because of these properties, among other things, a good ability to wind the fibrous web and to a good uniformity of the mechanical properties contribute to the fibrous web.

The property "thickness" preferably comprises the basis weight and / or during the production of locally available thickness, wherein the thickness according to the invention in the area of the headbox with preferential dilution water control, the press section and / or the calender is changed.

The property "modulus of elasticity", however, preferably comprises the modulus of elasticity in the direction of travel the fibrous web, in the transverse direction of the fibrous web and / or in the z-direction the fibrous web, wherein the at least one modulus of elasticity at least from the Fiber orientation, the web composition, the fiber type, the formation, the Transverse shrinkage, the moisture and / or the uniformity is determined.

• die Faserorientierung im Bereich des Stoffauflaufs hydraulisch und/oder mechanisch (Blende),
• die Bahnzusammensetzung im Bereich des Stoffauflaufs, der Siebpartie und/oder der Stoffaufbereitung, wobei sie zumindest den Füllstoffgehalt oder die Füllstoffverteilung umfasst,
• die Faserart im Bereich der Stoffaufbereitung, wobei sie den Anteil an Kurzfasern, Langfasern, Zellstoffart und/oder Holzart umfasst,
• die Formation im Bereich der Siebpartie, wobei sie zumindest die Flockung umfasst,
• der Querschrumpf im Bereich der Trockenpartie durch die vorhandene Trockensieb-Spannung,
• die Feuchte durch eine Beaufschlagung der Faserstoffbahn mittels mindestens eines Dampfblaskastens und/oder mindestens eines Düsenfeuchters und
• die Gleichmäßigkeit vor einem Leimauftrag und/oder einem Strichauftrag.

The parameters determining the modulus of elasticity are preferably changed in the following areas (actuators):

• the fiber orientation in the area of the headbox hydraulically and / or mechanically (iris),
• the web composition in the headbox, the wire section and / or the stock preparation, wherein it comprises at least the filler content or the filler distribution,
• the type of fiber in the field of stock preparation, comprising the proportion of short fibers, long fibers, type of pulp and / or type of wood,
• the formation in the area of the wire section, at least including the flocculation,
• the transverse shrinkage in the area of the dryer section due to the existing dryer fabric tension,
• the moisture by applying the fibrous web by means of at least one steam blower box and / or at least one nozzle moisturizer and
• the uniformity before a glue application and / or a coating application.

The object of the invention is in a device in the first embodiment solved by providing a winding machine with a carrier drum and a on a spool resulting winding roll, which together has a winding nip form, and that the carrier drum as a measuring roller for measuring the line force is formed along the web width.

The object of the invention is in a device in a second embodiment achieved by using a calender with a measuring roller for measuring the Train is. In this case, the measuring roller one or more calender rolls before be arranged guide roller. One arranged after several calender rolls Guide roller can also control the control of the calender be used.

The object of the invention is in a device in a third embodiment solved by having a press section with a measuring roller for measurement the train is.

The object of the invention is in a device in the fourth embodiment solved by having a Langnippresse, in particular a shoe press, with a measuring roller for measuring the web tension is. The measuring roller can behind be arranged the press nip.

The object of the invention is in a device in the fifth embodiment in that it has a drying section with a measuring roller for measuring the Train is. The measuring roller can be arranged at the end of the dryer section be.

The object of the invention is in a device in the sixth embodiment solved by providing a coating unit with a measuring roller for measurement the train is.

The object of the invention is in a device in the seventh embodiment solved by providing a measuring roller arranged between two guide rollers to measure the train. This is also a measurement of Web tension on a free, non-supported area of the fibrous web possible.

All previous designs have in common that the measuring roller is preferred is equipped with piezo elements along its length. The use of piezo elements ensures a very precise and fast measurement of the web tension. The Measured values can then be immediately forwarded to an actuator that controls the Correction of the deviation is carried out.

The measuring roller can of course also other Have measuring devices as piezo elements. The use of piezo elements has purely exemplary character.

Alternatively or additionally, however, it is also in a less expensive variant possible that the measuring roller is a multi-part measuring roller, at least one of the individual rollers is provided with at least one load cell.

If the measuring roller is at the same time a guide roller, it can have two functions at the same time.

The object of the invention is in a device in the eighth embodiment in that it has a device provided with an air cushion for Forwarding of the fibrous web is and that the means for forwarding the Fiber web along the web width with measuring devices for measuring a Dynamic pressure of the air cushion is provided. This non - contact alternative to the Forwarding of the fibrous web made possible by the measurement of the back pressure along the web width an elegant way to measure the train to then the web thickness or the modulus of elasticity as close as possible to the measuring location Body to correct.

The method according to the invention can preferably be in the range of at least one Winding machine, a calender, a press section, a drying section, one Coating unit and / or a free train of a manufacturing machine, in particular a paper or board machine.

Further features and advantages of the invention will become apparent from the following Description of a preferred embodiment with reference to the Drawing.

Figur 1

eine schematische Seitenansicht einer Wickelmaschine mit einer Messeinrichtung zur Messung des Bahnzugs;

Figur 2

eine weitere schematische Seitenansicht einer Wickelmaschine mit einer Messeinrichtung zur Messung der Linienkraft;

Figur 3

eine schematische Seitenansicht eines Kalanders mit einer Messwalze;

Figur 4

eine schematische Seitenansicht einer Pressenpartie mit einer Messwalze;

Figur 5

eine schematische Seitenansicht eines Streichaggregats mit einer Messwalze;

Figur 6

eine schematische Seitenansicht einer Trockenpartie mit einer Messwalze;

Figur 7

eine schematische Seitenansicht einer Langnippresse mit einer Messwalze;

Figur 8

eine schematische Seitenansicht einer zwischen zwei Leitwalzen angeordneten Messwalze;

Figur 9a

eine Vorderansicht einer mehrteiligen Messwalze;

Figur 9b

eine Seitenansicht der Messwalze gemäß Figur 9a;

Figur 10a

eine Vorderansicht einer Einrichtung zur berührungslosen Weiterleitung einer Faserstoffbahn in einem ersten Betriebszustand;

Figur 10b

eine Vorderansicht einer Einrichtung zur berührungslosen Weiterleitung einer Faserstoffbahn in einem zweiten Betriebszustand; und

Figur 11

eine schematische Seitenansicht einer Herstellungsmaschine.

Show it

FIG. 1

a schematic side view of a winding machine with a measuring device for measuring the web tension;

FIG. 2

a further schematic side view of a winding machine with a measuring device for measuring the line force;

FIG. 3

a schematic side view of a calender with a measuring roller;

FIG. 4

a schematic side view of a press section with a measuring roller;

FIG. 5

a schematic side view of a coating unit with a measuring roller;

FIG. 6

a schematic side view of a dryer section with a measuring roller;

FIG. 7

a schematic side view of a Langnippresse with a measuring roller;

FIG. 8

a schematic side view of a arranged between two guide rollers measuring roller;

FIG. 9a

a front view of a multi-part measuring roller;

FIG. 9b

a side view of the measuring roller according to Figure 9a;

FIG. 10a

a front view of a device for non-contact transmission of a fibrous web in a first operating state;

FIG. 10b

a front view of a device for non-contact transmission of a fibrous web in a second operating state; and

FIG. 11

a schematic side view of a manufacturing machine.

FIG. 1 shows a schematic side view of a winding machine 10 a carrying drum 11 and a winding roller 12. With regard to the other constructive Properties and procedural aspects of the winding machine 10 and the procedure of the winding method is based on the PCT publication WO 98/52858 A1 (US Pat. No. 6,129,305) (PR10706 WO) of the applicant; the content This application is hereby incorporated in full to the subject of this description made. The carrier drum 11 is in the running direction of the fibrous web. 1 a preferably provided with piezoelectric elements measuring roller 13 for measurement of the train z (arrow) upstream. If a deviation of the train z (Arrow) of a value range of permissible web tension values from an evaluation unit 14 is determined so he changed in a known manner accordingly.

The web tension z (arrow) can in a further embodiment also in the fibrous web 1 looped portion of the carrier drum 11 are measured. The measurement However, must in the direction of the fibrous web 1 before between the carrier drum 11 and winding roll 12 formed Nip N done to any influences To exclude the line force.

FIG. 2 shows a further schematic side view of a winding machine 20 with a measuring device 21 for measuring the line force F (arrow). The carrying drum 22 is equipped with piezoelectric elements, so that in the region of the winding nip 23 the line force F (arrow) measured along the width of the fibrous web 1 can be. If along the web width too strong differences in line force F (arrow) can be found in a corresponding place of the Production of fibrous web 1 Differences in thickness and modulus of elasticity balanced become.

FIG. 3 shows a schematic side view of a calender 30, which with a measuring roller 31 is equipped. The measuring roller 31 is in the running direction of the fibrous web 1 arranged in front of the calender rolls 32. However, the measuring roller can be arranged after the calender rolls, for example, the To be able to measure thickness transverse profile. With the measuring roller 31 of the train z (Arrow) along a width of a fibrous web 1 can be determined. From the train train differences the fibrous web 1 can then draw conclusions about the course the thickness and the modulus of elasticity of the fibrous web 1 drawn along the web width become. The measured web tension z (arrow) is in an evaluation device 33 compared with limit values of a value range of permissible web tension values. If the measured web tension z (arrow) of the limits of the value range permissible rail train values may, by changing at least a calender gap (nips) between the calender rolls 32 differences be balanced in thickness. Because the site and the location at the the differences in thickness are compensated, are close to each other, takes place Correction of the measured deviations almost at the same time. If the measuring roller 31 is equipped with piezo elements, is a very precise and fast Measurement of the web tension z (arrow) along the web width possible. Thus, the Measuring roller 31, the web tension z (arrow) of the fibrous web 1 and to a Forward evaluation unit 33.

4 shows a schematic side view of a press section 40, which with a measuring roller 41 is provided. The press section can in further execution also a Langnippresse, in particular a shoe press, have. The measuring roller 41 is disposed behind the felted press rolls 42 and 43. Conveniently, is the measuring roller 41, optionally also as a measuring roller 41 ', also provided with piezo elements. Thus, the measuring roller 41 (41 ') can pull the web Measure z (arrow) of the material web 13, and pass it on to an evaluation unit 44. According to the web tension values measured along the web width z (Arrow) can then be changed by a press nip formed by the press rollers 42 and 43 be to compensate for the thickness of the fibrous web 1. Besides, it is possible, the web 1 at the points where deviations on the web tension z (arrow) were detected, with a steam blower box 45 in some areas stronger or less strongly moisten to E modulus differences in the fibrous web 1 balance.

5 shows a schematic side view of a coating unit 50, the a measuring roller 51 has. Advantageously, the measuring roller 51 is also with Equipped with piezo elements. The measured by the measuring roller 51 web train z (Arrow) of the fibrous web 1 is passed on to an evaluation unit 52. If the determined by the measuring roller 51 web train z (arrow) of the limits deviates from the value range of permissible web tension values, one between the Rolls 53 and 54 formed nip be changed according to the thickness to compensate the fibrous web 1,

FIG. 6 shows a schematic side view of a drying section 60 with a Measuring roller 61. The measuring roller 61 measures the web tension z (arrow) of the fibrous web 1 and outputs the determined value to an evaluation unit 62 on. When the measured Web tension z (arrow) outside the value range of permissible web tension values is located here, not shown here moistening, the before or in the dryer section 60, the fibrous web 1 at the locations the material web where deviations in the web tension z (arrow) were detected, partially moisten stronger or less strongly. That way you can Differences in the modulus of elasticity can be compensated.

FIG. 7 shows a schematic side view of a coating unit 70 with a measuring roller 71, which measures the web tension z (arrow) of the fibrous web 1 and the Passes measured value to an evaluation unit 72. If the measured web tension z (Arrow) is outside the range of permissible web tension values, can between the rollers 73 and 74 lying nip be changed accordingly, to compensate for differences in thickness in the fibrous web 1.

8 shows a schematic side view of a guide roller 80 and a Guide roller 81, between which a measuring roller 82 is arranged. The measuring roller 82 is here between a free, non-supported area of the fibrous web 1. Since the measuring roller 82 is advantageously equipped with piezo elements is, even with this arrangement allows a reliable measurement of the train z (arrow) whose measured values are passed on to an evaluation unit 83 be in order to get as close as possible to the place of measurement Correction of the web thickness or the modulus of elasticity of the material web.

Figures 9a and 9b show views of a multi-part measuring roll 90, in the at least one of the individual rollers 91 with at least one load cell 92 is provided. The at least one load cell 92 is indicated by the arrows 93 (see Figure 9b) shown web train z (arrow) with a compressive force, the is shown by the arrow 94, applied. Thus, the train delivers z (arrow) a corresponding pressure force signal to a not shown here Evaluation unit is passed, if necessary to a corresponding Place the production of the fibrous web a change in web thickness or of the E-module.

Figures 10a and 10b each show a front view of a device 100 for contactless forwarding of the fibrous web 1. This is the device 100 generates an air cushion 101 provided with a dynamic pressure p (arrow), see FIG that the fibrous web 1 forwarded to the device 100 without contact becomes. By means of at least one measuring device not shown here for Measurement of the dynamic pressure p (arrow) along the web width can thus be a statement be taken over the height of the web train z (arrow) in the fibrous web 1. The higher the web tension z (arrow) in the fibrous web 1, the closer it is the fibrous web 1 to the device 100 at. Since the dynamic pressure p (arrow) all the more is greater, the denser the fibrous web 1 is applied to the device 100 (see FIG. 10b), the web tension z (arrow) to be measured is proportional to the dynamic pressure p (Arrow).

Finally, FIG. 11 shows a schematic side view of a production machine 110. The manufacturing machine has at least one headbox 111, a wire section 112, a press section 113, a dryer section 114 and a winding machine 115 and serves to produce a fibrous web 1, in particular a paper or board web. The manufacturing machine shown in Figure 11 110 additionally has a coating unit 116, a nozzle moistener 117 and a calender 118 on.

This manufacturing machine 110 is particularly suitable for implementation and Application of the method according to the invention for controlling at least a process-relevant property during the production of a fibrous web 1, wherein the process-relevant property during the production of the fibrous web 1 at least the winding hardness (radial stress), the tensile stress in the individual layers of the winding roll 12 and / or the smoothness-quality of a smoothing process includes.

The thickness encompasses the weight per unit area and / or during production locally existing thickness and is in the area of the headbox 111 with vorzugsweiser Dilution water control, the press section 113 and / or the Kalander changed 118.

The at least one modulus of elasticity comprises the modulus of elasticity in the direction of the fibrous web 1, in the transverse direction of the fibrous web 1 and / or in the z-direction of the fibrous web 1 and is at least determined by the fiber orientation, the web composition, the type of fiber, the formation, the transverse shrinkage, the humidity and / or uniformity.

The parameters determining the modulus of elasticity are preferably those already described Areas (actuators) of the manufacturing machine 110 changed: in the area of the stock preparation, not shown, in the area of the headbox 111, in the area of the wire section 112, in the area of the press section 113, in the area the drying section 116, in the area of the nozzle moisturizer 117 and / or in the area of the calender 118.

In summary, it should be noted that the invention provides a method of initially created type, which provides an additional way to regulate at least one process-relevant property of the manufacturing process the fibrous web provides a high quality finished fibrous web to reach and ensure.

LIST OF REFERENCE NUMBERS

1

Fibrous web

10

winder

11

carrying drum

12

reel

13

measuring roll

14

evaluation

20

winder

21

measuring device

22

carrying drum

23

winding gap

30

calender

31

measuring roll

32

calendar roll

33

evaluation

40

press section

41, 41 '

measuring roll

42.43

press roll

44

evaluation

45

steam blow

50

coater

51

measuring roll

52

evaluation

53, 54

roller

60

drying section

61

measuring roll

62

evaluation

70

coater

71

measuring roll

72

evaluation

73, 74

roller

80.81

guide roll

82

measuring roll

83

evaluation

90

Multi-part measuring roller

91

roller

92

Load cell

93

arrow

94

arrow

100

Facility

101

bubble

110

making machine

111

headbox

112

Wire section

113

press section

114

drying section

115

winder

116

coater

117

nozzle unit

118

calender

F

Line power (arrow)

N

Winding nip

p

Back pressure (arrow)

z

Railway train (arrow)

Claims (28)

Method for controlling at least one process-relevant property during the production of a fibrous web (1), in particular a paper or board web, with a production machine (110), in particular a headbox (111), a wire section (112), a press section (113 ), a drying section (114) and a paper or board machine having a winding machine (10, 115),
by determining at least one local change and / or at least one local difference of at least one first characteristic transverse profile of the fibrous web (1)
by measuring at least one mechanical parameter of the fibrous web (1) at least two points distributed over the width of the fibrous web (1) and
by influencing the at least one first characteristic transverse profile at the at least one location as a function of the local change or the local difference by changing at least one second characteristic transverse profile of the fibrous web (1) at at least one further location,
wherein the at least one first characteristic transverse profile is the line force (F) or an equivalent size, in particular the pressure, and / or the web tension (z) or an equivalent size. Method according to claim 1,
characterized in that the process-relevant property during the production of the fibrous web (1) comprises at least the winding hardness, the tensile stress in the individual layers of the winding roll (12) and / or the smoothness-quality of a smoothing process. Method according to claim 1 or 2,
characterized in that the at least one second transverse property profile of the fibrous web (1) comprises at least the thickness and / or at least one modulus of elasticity. Method according to claim 3,
characterized in that the thickness comprises the basis weight and / or the thickness present locally during manufacture, and
that the thickness in the area of the headbox (111), preferably having dilution water control, of the press section (113) and / or of the calender (117) is changed. Method according to claim 3,
characterized in that the at least one modulus of elasticity comprises the modulus of elasticity in the running direction of the fibrous web (1), in the transverse direction of the fibrous web (1) and / or in the z-direction of the fibrous web (1). Method according to claim 5,
characterized in that the at least one modulus of elasticity is determined at least by fiber orientation, web composition, fiber type, formation, transverse shrinkage, moisture and / or uniformity. Method according to claim 6,
characterized in that the fiber orientation in the area of the headbox (111) is hydraulically and / or mechanically changed. Method according to claim 6,
characterized in that the web composition comprises at least the filler content or the filler distribution and is changed in the area of the headbox (111), the wire section (112) and / or the stock preparation. Method according to claim 6,
characterized in that the type of fiber comprises the proportion of short fibers, long fibers, pulp and / or wood species and is changed in the field of stock preparation. Method according to claim 6,
characterized in that the formation comprises at least the flocculation and is changed in the region of the wire section (112). Method according to claim 6,
characterized in that the transverse shrinkage is changed by the existing dryer fabric tension in the area of the dryer section (114). Method according to claim 6,
characterized in that the moisture is changed by acting on the fibrous web (1) by means of at least one steam blower box (45) and / or at least one Düsenfeuchters (117). Method according to claim 6,
characterized in that the uniformity is changed before a glue application and / or a coating application. Apparatus for carrying out the method according to at least one of claims 1 to 13,
characterized in that it is a winding machine (10, 115) with a carrier drum (11) and a winding roll (12) formed on a spool, which together form a winding nip (N), and
in that the carrier drum (11) is designed as a measuring roller for measuring the line force (F) along the web width. Apparatus for carrying out the method according to at least one of claims 1 to 13,
characterized in that it is a calender (30, 118) with a measuring roller (31) for measuring the web tension (z). Device according to claim 15,
characterized in that the measuring roller (31) is a before or after several calender rollers (32) arranged guide roller. Apparatus for carrying out the method according to at least one of claims 1 to 13,
characterized in that it is a press section (40, 113) with a measuring roller (41) for measuring the web tension (z). Apparatus for carrying out the method according to at least one of claims 1 to 13,
characterized in that it is a Langnippresse, in particular a shoe press, with a measuring roller (41) for measuring the web tension (z). Device according to claim 17 or 18,
characterized in that the measuring roller is arranged behind the press nip. Apparatus for carrying out the method according to at least one of claims 1 to 13,
characterized in that it is a drying section (60, 114) with a measuring roller (61) for measuring the web tension (z). Device according to claim 20,
characterized in that the measuring roller (61) at the end of the drying section (60, 114) is arranged. Apparatus for carrying out the method according to at least one of claims 1 to 13,
characterized in that it is a coating unit (50, 70, 116) with a measuring roller (51) for measuring the web tension (z). Apparatus for carrying out the method according to at least one of claims 1 to 13,
characterized in that it comprises a between two guide rollers (80, 81) arranged measuring roller (82) for measuring the web tension (z). Device according to one of claims 14 to 23,
characterized in that the measuring roller (11, 31, 41, 51, 61, 71, 82) is fitted over its length with piezo elements. Device according to one of claims 14 to 23,
characterized in that the measuring roller (11, 31, 41, 51, 61, 71, 82) is a multipart measuring roller (90) whose individual rollers are provided with at least one load cell each (92). Device according to one of claims 14 to 25,
characterized in that the measuring roller (11, 31, 41, 51, 61, 71, 82) is a guide roller (80, 81). Apparatus for carrying out the method according to at least one of claims 1 to 13,
characterized in that it is provided with an air cushion (101) means (100) for conveying the fibrous web (1) and
that the device (100) is provided for transferring the fibrous web (1) along the web width with measuring devices for measuring a dynamic pressure (p) of the air cushion (101). Application of the method according to at least one of claims 1 to 13 in the region of at least one winding machine (10, 115), a calender (30, 118), a press section (40), a dryer section (60, 114), a coating unit (50, 70, 116) and / or a free draw of a manufacturing machine (110), in particular a paper or board machine.

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