EP3423627B1 - Cylinder paper machine - Google Patents

Description

The invention relates to a paper machine for the production of paper, the paper machine having a machine-wide pulp suspension feed, a trough with a DC rotary sieve rotating therein, a trough inlet and a nonwoven removal device.

Such paper machines are known, in particular for the production of security papers and banknote papers with watermarks and / or security threads. However, paper machines with DC rotary sieves are still occasionally in use on older machines for the production of cardboard or paperboard. An example of such a prior art paper machine is described below. The known paper machines of this type have this disadvantage that they work without a defined headbox. In particular, there is no controlled velocity progression between the point of entry of the pulp suspension into the trough up to the point at which the sieve cylinder forms a channel with the sieve trough. The course of the flow is essentially determined by the open surface of the trough.

Such paper machines are known in the art, for example from US 2 243 773 A , of the GB 392 467 A , of the US 2 051 233 A and the US 2,191,999 A known.

Negative velocity gradients, that is, delays in the flow velocity, disadvantageously arise in the trough feed, although reverse flow or standing suspensions may also occur. Such areas adversely affect the flocculation state of the suspension and thus adversely affect the formation of the formed sheet. By the not well controlled Speed is also when introducing security threads to problems. These must be placed very precisely in the formed paper. As the flow rate increases, positionally accurate embedding of the threads in the suspension becomes increasingly problematic due to cross flows occurring. The thread can oscillate uncontrollably, which makes the placement in the formed paper less accurate. A further problem is that the fiber orientation and thus the longitudinal or transverse ratio of the sheet strength properties (eg tear length, tear propagation resistance, etc.) develop unfavorably.

The aim of the present invention is to improve the flow conditions in the trough so that no negative velocity gradients, no backflow or dead zones between the flow entering the trough and the transition into the channel, formed from trough and round screen arise. Furthermore, the invention allows an adaptation of the speed at the transition into the channel regardless of the geodesic level in the trough. In this way, the speed of paper production, which is in the prior art at 30-100 m / min, with the same screen cylinder diameter can be significantly increase. Furthermore, the accuracy of the positioning of security threads should be increased even at higher speeds of paper formation.

The paper machine according to the invention solves the above-described disadvantages by the features of the claims and the following description with the figures.

• Fig. 1 zeigt schematisch einen Schnitt durch eine Papiermaschine gemäß Stand der Technik.
• Fig. 2 zeigt schematisch den Schnitt durch ein erstes Ausführungsbeispiel gemäß Erfindung und
• Fig. 2a zeigt ein geändertes Ausführungsbeispiel.
• Fig. 3 zeigt in teilweisem Schnitt ein Detail.
• Fig. 4 zeigt eine Aufsicht auf dieses Detail.
• Fig. 5 zeigt ein drittes Ausführungsbeispiel.
• Fig. 6 zeigt ein weiteres Ausführungsbeispiel mit zugehörigem Regelschema und
• Fig. 7 zeigt eine Ausführung mit verstellbarer Überlaufleiste.

Hereinafter, the prior art and the invention will be described with reference to the drawings.

• Fig. 1 schematically shows a section through a paper machine according to the prior art.
• Fig. 2 schematically shows the section through a first embodiment according to the invention and
• Fig. 2a shows a modified embodiment.
• Fig. 3 shows a detail in partial section.
• Fig. 4 shows a view of this detail.
• Fig. 5 shows a third embodiment.
• Fig. 6 shows a further embodiment with associated control scheme and
• Fig. 7 shows a version with adjustable overflow bar.

Fig. 1 shows a paper machine according to the prior art. The paper machine essentially comprises a trough 1 with a circular sieve 2 running therein with the direction of rotation 3. Via a pulp suspension inlet 4, the suspension, which consists essentially of water, paper fibers and various additives, via the cross-flow distributor 5, a turbulence insert 6 and the inlet nozzle 7 out into the trough inlet 8 and passes from there via the trough channel inlet 9 in the flow direction 10 in the channel 11, which is formed between the round screen 2 and the trough 1. The cross-sectional ratio between trough channel inlet 9 and trough channel outlet 12 can be changed by adjusting the position of the circular sieve axis 13. The direction of rotation 3 of the round screen 2 and the flow direction 10 of the pulp suspension is rectified.

By constant inflow of the suspension is formed in the trough inlet 8 of the suspension mirror A1, while in the interior of the round screen 2, the suspension mirror A2 prevails. The difference in pressure caused by the difference in height causes the flow of the liquid constituent of the suspension into the interior of the round screen and the corresponding deposition of a fibrous web on the surface of the round screen. The fibrous web is removed by a web removal device 14, which here consists of a couch roll 15 and a take-off web 16. By Abnahmevlies 16 the fibrous web is removed from the round screen and fed to further processing.

The couch roll 15 is preceded in this embodiment, a so-called Egoutteur 17, which serves to equalize the leaf formation. By embossing or other watermark inserts on the round screen 2 watermarks can be provided.

Residual suspension, which flows over the trough channel outlet 12, can be withdrawn via the outlet 18 and recycled.

It should be noted that the suspension mirror A1 in the trough inlet 8 is limited in its vertical position by the diameter of the round screen 2 and the position of the couch roll 15. Therefore, the differential pressure between A1 and A2 can not be increased arbitrarily. This limits the speed of the paper machine.

In the pulp suspension feed 4, the velocity profiles are drawn at different locations. While at the beginning of the turbulence insert 6, a relatively homogeneous flow is observed, the flow path in the direction of the round screen 2 is inhomogeneous and takes a negative course. This leads to the aforementioned difficulties.

It should again be emphasized that the illustration of this prior art is only an example and many modifications are possible. In all these paper machines, however, the problem is uniform that the trough inlet 8 has a free suspension mirror by the round screen 2 rotates.

The Fig. 2 shows a simplified example of a paper machine according to the invention, wherein like reference numerals have the same meaning. There are only the machine parts essential for the present invention shown, so that the devices such as couch roll 15, Vliesabnahmevorrichtung 14 and Egoutteur 17 are not shown, but the same as in Fig. 1 can be arranged.

According to the invention, the trough inlet 8 has a flow-guiding device 20. This comprises a covering the liquid level and the suspension flow continuously accelerating in the trough channel inlet 9 guiding cover 19. The cover 19 comprises a rigid upper lip 21 bent downwards at the end, and subsequently a flexible skirt 22, which is arranged or can be arranged adjacent to the round screen 2. This flow guide extends over the entire length of the round screen 2, as far as it is acted upon by the pulp suspension and is sealed to the end wall of the trough.

The angular position of the cover 19 to the inflow into the channel 11 is adjustable and changeable by a hinge 23. Furthermore, the position of the skirt 22 on the upper lip 21 is adjustable by a locking device 24. By this adjustment, the pulp suspension feed 4 can be adapted to the other conditions, such. B. to changed diameter of the round screen. Furthermore, the upper lip 21 is fixed with its pivot joint 23 on a sliding plate 25 which is displaceable and attached to the tray inlet to adjust the distance to the round screen 2 can. With the displaceability of the skirt 22 relative to the upper lip 21, it is also possible to adjust the apron protrusion.

The apron is attracted by the round screen by the pressure difference between the pressure inside the round screen 2 and the pressure in the tray inlet 9, whereby the sealing effect is created. Due to the lateral sealing of the upper lip 21 and the skirt 22 to the side trough wall is located in the formed from the upper lip 21 (with skirt 22) and cylinder mold Rundsieb-apron gusset 41, no pulp suspension. There is thus no suspension mirror A1 in this gusset. A1 is in Fig. 2 represented as a theoretical level by dashed lines.

This theoretical level corresponds to the pressure generated by the feed pump in the inlet channel (nozzle). As the pressure in the nozzle increases, so does the theoretical level (also over the trough edge).

In order to increase the area in which the apron 22 rests on the cylinder mold, without adversely affecting the flow conditions in the nozzle channel, it may be necessary to design the shape of the upper contour of the upper lip 21 and the attachment point of the skirt 22 so that the outlet tangent of the Apron 22 comes to rest on the round cylinder at a desired point above the rigid end point of the upper lip 21. This can be done by a attached to the upper lip 21 contour body 42, as in Fig. 2a is shown. The contoured body 42 may be interchangeable to provide different contours.

The upper contour of the upper lip 21 ensures that, despite the laying of the attachment point (locking device 24), a sufficient gusset is formed. This gusset is required for the introduction of so-called window threads. Window threads are only incompletely covered and embedded by fibers on the side facing the sieve. The thread is partially covered by fibers on this side. To achieve this, the thread is brought to the screen already before the first dewatering point of the round cylinder. The support point of the thread is therefore in the gusset in front of the contact point of the skirt 22 in the gusset. The thread is only partially washed by the suspension.

Such a variant with guided on the upper lip top apron 22 and thread guide 26 is shown in detail in the figure Fig. 2a shown.

In Fig. 2 and Fig. 2a is also the arrangement of a guide tube 26 located, which serves a thread z. B. to embed a metallized security thread made of plastic in the fibrous web to be formed. The arrangement of the guide tube or a juxtaposed series of such guide tubes is based on the Fig. 3 described.

The Fig. 3 and 4 show this arrangement of the guide tube 26, which is fixed in this embodiment, for example, only in a ball joint 27, whereby the position of the guide tube 26 is adjustable. The ball joint 27 is mounted in a sealing plate 28 which is displaceable in the horizontal direction to allow the lateral adjustment (transverse to the web) of the position of the guide tube 26.

Depending on the size of the paper products to be formed, for example, depending on the size of the banknotes, it is possible, for example, to fasten such a guide tube 26 to the upper lip 21 every 15 cm. The guide tubes 26 can also be oscillated via an external drive, if such an offset of the securing thread of ± 2 mm to ± 15 mm in the paper web is desired.

In Fig. 3 is still the hinge 23 and the displacement plate 25 is shown, which is fastened on a machine-fixed construction element 29 in a corresponding displacement position.

Fig. 5 shows a further embodiment in which in the trough inlet 8 and the cover 19 upstream of a suspension stowage box 30 is arranged. By arranging this suspension box 30, the hydrostatic pressure, which corresponds to the dewatering pressure through the screen, can be increased, which is formed by the difference to the suspension level A3 in the suspension stowage box 30 and the suspension mirror A2 set in the interior of the round screen. The suspension stowage box 30 is closed at the top to form an air cushion 31, wherein an inlet and outlet line 32 may optionally be provided for regulating the pressure and the suspension level. With reference numeral, the foam overflow 40, an overflow is drawn in order to derive excess suspension or foam formed can.

This type of pressure-vacuum control can often be found in headboxes of the paper industry. About the air cushion pressure, the level A3 is kept constant. High air cushion pressure therefore corresponds to a higher level of stagnation than A3 and low pressure (vacuum) corresponds to a lower level. The stagnation level thus corresponds to the pressure in the inlet channel (nozzle). In this way, a "feed level" is realized, which can be arbitrarily set in contrast to an open trough namely also above the theoretical level A1 or below this.

A regulation for this is in Figure 6 shown.

For example Figure 5 the level is generated solely by the pump pressure. The lowest possible "level" corresponds to the highest point of the upper lip.

As a detail, it should be noted that the pulp suspension feed from the crossflow distributor 5 is guided via a perforated plate 33 into a settling chamber 34. Furthermore, the pulp suspension flows through a turbulence insert 6, so that the most uniform flow profile is generated in the trough channel inlet 9 a to achieve balanced velocity profile and pulp concentration over the entire cross section.

In Fig. 6 the scheme of a further embodiment variant with associated control and line devices is shown. The pulp suspension passes through the cross-flow distributor 5 through a first turbulence insert 34 into the suspension stowage box 30, and a second turbulence insert 35 into the trough inlet 8. The pressure in the air cushion 31 can be controlled via an air pressure source 36 and associated control valves 37. Furthermore, there is a control bypass 38 which cooperates with the white water tank and the foam overflow 40 for the feed quantity of the pulp suspension.

The Fig. 7 shows schematically the view in the direction of the Rundsiebachse 13. The same design features are provided with the same reference numerals, as in the preceding figures. As in the previous embodiments, the round screen 2 is adjustable in its position within the trough 1, whereby the geometry of the flow channel is adjustable. The trough 1 has at the outlet 18 on the suspension mirror A4 in the flow of determining or largely influencing overflow bar 44. The position of the overflow strip 44 is adjustable both in height, as well as in their distance from the round screen 2.

This adjustability of the overflow allows or facilitates on the one hand the removal and installation of the round screen in the trough and on the other hand determines the position of the overflow strip 44, the suspension mirror A4 and thus the pressure ratio in the round screen. The adjustment is made by the adjusting member 47 and the pivot 46. The height of the position of the overflow strip is made by moving according to arrow 48th

The smaller and higher the overflow gap at the outlet and thus at the overflow strip 44, the higher the dewatering pressure at the round screen. For example, the distance between the round screen and Überlauleiste between 2 mm and 60 mm are, this information is only an example.

In Fig. 7 it can also be seen that the trough 1 is reinforced by ribs 45 in order to keep the trough 1 sufficiently rigid. Both the trough 1, as well as the rotatable round screen 2 are interchangeable.

In the suspension flow inlet here is also an air-pressure-controlled arrangement with a suspension storage box 30 is provided, the air cushion pressure can be controlled by the supply and discharge line 32 for air.

The displacement plate 25 has to adjust the position of the upper lip 21 with your skirt 22 on a sliding gear 43, whereby the position of the upper lip 21 and skirt 22 can be adjusted or changed.

To the guide tube 26 is still to be noted that this may be connected to a water or air pressure device to shoot at the beginning of paper making the thread with pressure down to the round screen can.

At the in Figure 7 illustrated arrangement is to be noted that the inlet channel with the upper lip 21 and the overflow strip 44 are arranged on the screen cylinder such that the proportion of the screen cylinder has the direct atmospheric contact, is less than 30 degrees. The direct contact of the screen to the atmosphere is limited by the apron 22, the fiber suspension in the trough and the fiber web formed until it is removed by the couch roll 15. This arrangement makes it possible to further increase the drainage performance of the screen cylinder by a blower suction or fan.

The FIGS. 2 to 7 show each modified construction elements, the arrangement of which are not limited to the specific representations in the figures, but it can be the features and design details provided in all embodiments, or even omitted.

For understanding the invention, the following is still to be considered.

In such paper machines, the longitudinal or transverse ratio and the fiber orientation are further important paper properties. The longitudinal or transverse ratio and the fiber orientation are determined solely by the flow velocity in the transition region and the geometry of the channel formed by the trough wall and the screen cylinder.

1. 1. der Zulaufmenge zum Rundsieb,
2. 2. dem Stauziel im Trog,
3. 3. dem Einlaufquerschnitt und
4. 4. der Geometrie des aus Trogwand und Siebzylinder gebildeten Kanals.

This speed profile and thus the fiber orientation and the longitudinal or transverse ratio of the strength properties of the paper are dependent on four factors:

1. 1. the feed rate to the round screen,
2. 2. the stowage target in the trough,
3. 3. the inlet cross-section and
4. 4. the geometry of the channel formed by trough wall and screen cylinder.

For given round cylinder and trough of the resulting trough wall and screen cylinder channel is adjusted so that it continuously tapers from beginning to end, according to the drainage rate of the screen. By the horizontal displacement of the screen cylinder, the inlet cross section is changed in the channel, but also the tapered channel. This is therefore only permitted to a limited extent.

Since the inlet takes place in the prior art in an open trough, the stagnation level must coincide approximately with the upper edge of the inlet cross-section. If the level is significantly above this point, there is an unfavorable delay of the pulp suspension when entering the trough. If the suspension level is below, there is also inadmissible turbulence.

The determination of the water level (top edge) given the cylinder diameter are constructive narrow limits. These limits result from the position of the dandy cutter and the squeeze roller wrapped around the felt. These rollers must be above the suspension level. In addition, the suspension wetted circumference of the cylinder should represent a maximum. Furthermore, the water level is influenced by the height of the overflow edge at the outlet.

• der Position der ablaufseitigen Überlaufkante,
• dem Entwässerungswiderstand am Rundsiebzylinders (abhängig von Stoffdichte und Maschenweite) und
• dem Strömungswiderstand in dem zwischen Trog und Siebzylinder gebildeten Kanal.

In practice, the inflow at the given stowage level in the trough is dependent on:

• the position of the outlet side overflow edge,
• the drainage resistance at the round cylinder (depending on consistency and mesh size) and
• the flow resistance in the channel formed between trough and screen cylinder.

It is now state of the art to influence the fiber orientation and thus the longitudinal or transverse ratio of the strength properties of the paper and the formation of the sheet on the feed rate and the displacement of the screen cylinder. However, due to the relationships shown, this is only possible and expedient to a very limited extent. The limited influence of the open system on these sheet properties represents a significant disadvantage of the DC Rundsiebs.

The invention described on the one hand is based on the problem of improving the flow conditions in the trough such that no negative velocity gradients, backflows or dead zones arise.

This is ensured by a flexible upper lip with a flexible apron. The upper lip is sealed to the lateral trough wall. In the nozzle area, the upper lip has a flexible apron, which seals the cylinder. The apron is variable in length. It can either be directly connected to the end of the upper lip or mounted anywhere on the lip top and hanging it over the lip end. The upper lip is horizontally and vertically adjustable to ensure an optimal nozzle geometry, depending on the cylinder diameter. For this purpose, the lip has a swivel joint on the inlet side with a horizontal adjustment and optimally a vertical adjustment. The cylinder is horizontally displaceable in the trough as in the prior art.

In order to ensure the threading of security paper and banknote paper, the upper lip has a guide tube passage.

Each guide tube is individually adjustable to ensure the desired position in the paper. In addition, the guide tube in the sealed passage has a ball joint, whereby a charging in operation is possible.

The invention is also based on the problem that the speed at the transition into the channel with open DC round wire can not be influenced independently of the geodetic level of the suspension. In addition to the criterion that the flow from the inlet to the nozzle to the transition into the channel should have an undisturbed and continuously accelerated flow profile, it is also crucial to keep the velocity in the channel approximately in a constant relationship to the speed.

• v = Strahlgeschwindigkeit in m/sec
• g = Erdbeschleunigung m/sec²
• h = Stauhöhe m
• f = Schürzen-Faktor (empirisch)

This is done by the approach described below. The velocity of the jet at the nozzle end can be determined according to the following formula: $${\mathrm{<figure-callout\; id="2"\; label="v"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">v</figure-callout>}}^2=2\mathrm{G}\mathrm{H}/\mathrm{f}$$

• v = jet velocity in m / sec
• g = gravitational acceleration m / sec ²
• h = damming height m
• f = apron factor (empirical)

1. 1. Die Auslaufgeschwindigkeit wird durch eine drehzahlgeregelte Pumpe bestimmt; sie arbeitet also hydraulisch.
2. 2. Der Suspensionsstand über dem Düsenende ist niveaugeregelt und hat bei allen Geschwindigkeiten die gleiche Höhe. Die Auslaufgeschwindigkeit und die dazugehörige Stauhöhe werden durch einen Luftpolster erreicht und automatisch geregelt. Bei langsamen Geschwindigkeiten, wenn der fixierte Suspensionsstand die erforderliche Stauhöhe übersteigt, wird der Luftpolster auch automatisch in den Vakuumbereich geregelt. Hierdurch lässt sich der Stoffauflauf auch bei Geschwindigkeiten ab 30 m/min und bis weit über 150 m/min betreiben. Eine hierzu geeignete Druck- und Vakuumregelung mit einem entsprechenden Stoffauflauf ist in Fig. 6 gezeigt.

Bezugszeichenliste (1) Trog (28) Abdichtplatte (2) Rundsieb (29) Konstruktionselement (3) Drehrichtung (30) Suspensions-Staukasten (4) Faserstoffsuspensionszulauf (31) Luftpolster (5) Querstromverteiler (32) Zu- und Ableitung (6) Turbulenzeinsatz (33) Lochplatte (7) Zulaufdüse (34) Erster Turbulenzeinsatz (8) Trogzulauf (35) Zweiter Turbulenzeinsatz (9) Trogkanaleinlauf (36) Luftdruckquelle (10) Strömungsrichtung (37) Regelventile (11) Kanal (38) Regelbypass (12) Trogkanalauslauf (39) Siebwasserbehälter (13) Rundsiebachse (40) Schaumüberlauf (14) Vliesabnahmevorrichtung (41) Rundsieb-Schürzen-Zwickel (15) Gautschwalze (42) Konturkörper (16) Abnahmevlies (43) Verschiebegetriebe (17) Egoutteur (44) Überlaufleiste (18) Ablauf (45) Rippen (19) Abdeckung (46) Drehgelenk (20) Strömungsleitvorrichtung (47) Verstellorgan (21) Oberlippe (48) Pfeil (22) Schürze (23) Drehgelenk (A1) Suspensionsspiegel (24) Feststellvorrichtung (A2) Suspensionsspiegel (25) Verschiebeplatte (A3) Suspensionsspiegel (26) Führungsrohr (A4) Suspensionsspiegel (27) Kugelgelenk For this purpose, there are two solutions for the closed design of the DC round screen, which are used depending on the speed range traveled.

1. 1. The discharge speed is determined by a speed-controlled pump; So she works hydraulically.
2. 2. The suspension level above the nozzle end is level-controlled and has the same height at all speeds. The discharge speed and the associated damming height are achieved by an air cushion and automatically controlled. At slow speeds, when the fixed suspension level exceeds the required damming height, the air cushion is also automatically controlled in the vacuum area. This allows the headbox to operate even at speeds from 30 m / min to well over 150 m / min. A suitable pressure and vacuum control with a corresponding headbox is in Fig. 6 shown.

<B> LIST OF REFERENCES </ b> (1) trough (28) sealing (2) Round Screen (29) design element (3) direction of rotation (30) Suspension storage box (4) Pulp suspension feed (31) bubble (5) Cross-flow distribution (32) Inlet and outlet (6) turbulence generator (33) perforated plate (7) Inflow (34) First turbulence insert (8th) trough feed (35) Second turbulence insert (9) Trough channel inlet (36) Air pressure source (10) flow direction (37) control valves (11) channel (38) usually bypass (12) Trough channel outlet (39) white water tank (13) Rundsiebachse (40) Foam overflow (14) Fleece removal device (41) Cylinder mold aprons Zwickel (15) couch roll (42) contoured body (16) , fleece (43) shift gear (17) Egoutteur (44) About scrollbar (18) procedure (45) ribs (19) cover (46) swivel (20) flow director (47) adjusting (21) upper lip (48) arrow (22) apron (23) swivel (A1) suspension mirror (24) Locking device (A2) suspension mirror (25) sliding plate (A3) suspension mirror (26) guide tube (A4) suspension mirror (27) ball joint

Claims (11)

1. A paper machine for manufacturing paper, wherein the paper machine has a machine-wide fiber-suspension-inlet (4), a vat (1) with a uniflow cylinder mold (2) rotating therein, a vat inlet (8), and a fiber web pickup device (14), wherein a vat channel (9) is formed between the uniflow cylinder mold (2) and the vat (1), and wherein the vat inlet (8) has a flow guiding device (20), and the flow guiding device (20) has a cover (19) that covers the suspension level (A1) of the fiber suspension in the vat inlet (8) and continuously accelerates the suspension stream while guiding it into the vat channel inlet (9), characterized in that the cover (19), viewed in the flow direction, has a rigid top lip (21) that is curved downwardly at the end, and an adjoining flexible skirt (22) that may be situated so as to rest against the cylinder mold (2).
2. The paper machine according to Claim 1, characterized in that the cover (19) has a contour body (42) on the top side that fixes the top contact point of the flexible skirt to the cylinder mold at an intended point and with a defined cylinder mold-skirt gusset (41), without influencing the flow channel.
3. The paper machine according to one of Claims 1 or 2, characterized in that the angular position of the cover (19) with respect to the inflow direction (10) in the vat channel inlet (9) is adjustable and changeable by means of a rotary joint (23).
4. The paper machine according to Claim 3, characterized in that the cross section of an inlet channel of the flow guiding device (20) upstream from the inlet into the vat channel inlet (9) is adjustable and changeable by means of the rotary joint (23).
5. The paper machine according to one of Claims 3 or 4, characterized in that the position of the flow guiding device (20) into the vat channel inlet (9) is adjustable and changeable by means of the rotary joint (23) of the cover (19) in order to adapt to different cylinder mold diameters.
6. The paper machine according to one of Claims 3 to 5, characterized in that the top lip (21) together with the rotary joint (23) is fastened to a sliding plate (25) that can be displaced in relation to the vat inlet and fixed in order to adjust the distance from the cylinder mold (2).
7. The paper machine according to one of Claims 1 to 6, characterized in that the skirt (22) is displaceable in relation to the top lip (21) in order to adjust the skirt overhang.
8. The paper machine according to one of Claims 1 to 7, characterized in that the top lip (21) has an opening for receiving one or more guide tubes (26) for the embedding of threads, preferably security threads, into the fiber web that is formed on the cylinder mold.
9. The paper machine according to Claim 8, characterized in that the guide tube (26) is situated in a joint body, preferably a ball joint (27), which is supported in a sealing plate (28) that is sealingly displaceable in a recess in the top lip.
10. The paper machine according to one of Claims 1 to 9, characterized in that a suspension storage compartment (30) is arranged upstream from the vat inlet (8), via which a hydrostatic pressure may be built up that is higher than the maximum pressure due to the highest level of the fiber suspension that is achievable at the cylinder mold (2).
11. The paper machine according to one of Claims 1 to 10, characterized in that an outlet (18) is provided, via which residual fiber suspension that overflows the vat channel outlet (12) is removed and recycled, and in that at the outlet (18) the vat (1) has an overflow bar (44) that determines the suspension level (A4) in the outlet, and the position of which is adjustable with regard to the height and the distance from the cylinder mold.

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