EP0711723B1 - Device for a fully non-contact direction change of a moving web - Google Patents

Abstract

The inner side of the web (3), in the deflection area, has an inner compartment connected to the atmosphere and separated from an outer compartment connected to a vacuum. A gap is formed between the deflection surface and the edge of the web, caused by the effect of the pressure difference between the two compartments. A flow duct (23) guiding the web and connecting areas of different pressure is positioned at the inlet and or outlet (9, 10) of the deflector surfaces' deflection area. The duct walls are formed by guide pieces (12, 13), the side walls (14) of the chamber (15) forming the outer compartment, and the moving web. The deflection surfaces have a convex cylindrical body (21) with disc shaped end edge surfaces (28) with larger radius than the cylindrical body.

Description

The invention relates to a device for deflecting a moving path, which is one of the deflection area inner space allocated by the inner side of the web separates the outer space assigned to the outer side, where the outer space is formed by a chamber that with a vacuum source is connected, and the inner space connected to the atmosphere and in the area of Edges of the web each a deflection surface is arranged between the and the associated edge of the web below the influence of the pressure difference between the two rooms forms a gap.

In the German patent DE 35 12 316 a device described in which a continuous path Changes direction without the need for the web deflection concave on the inner side of the web Web surface must be touched. The principle of operation is based on the application of a differential pressure between the concave inside when the deflection Track surface and the outer convex side of the on the deflection path, a cylindrical path. This happens in that the outer space in the deflection area is formed by a chamber with a vacuum source is connected, and in that the inner Space is connected to the atmosphere and that for sealing the chamber versus the atmosphere in the Entry and exit zone of the deflection area itself over the web width sealing elements with the interact when deflecting the outer side of the web. When determining the type of these sealing elements and the How they interact with the outside On the web side, it is important to have an effective seal the chamber from the atmosphere can be and no damage to the web Product from the interaction of the sealing elements with the outer side of the web results.

The two embodiments described in the patent DE 35 12 316 are described, set as sealing elements on the outer side of the track two rotatably mounted Rolls ahead, each one sealing point with the web and one form a second sealing point with the chamber wall. This embodiment allows a very efficient sealing of the Chamber because of the contact between the rollers and air leakage on the outside of the web first sealing point is completely excluded. There too the second sealing point between the roller and the chamber wall designed in the form of a long and very narrow gap allows the use of rotatable rollers as Sealing elements a very effective partitioning of the chamber towards the atmosphere, which creates numerous Advantages in the design of the deflection box and the Interpretation of the vacuum source result.

A major disadvantage of this embodiment Sealing rolls is the inevitable touch of the outer web side through the surface of the rollers what the Use of this embodiment in connection with Excludes web materials during the redirection not be touched on either of the two web surfaces allowed to. But it may also be that the train on the outer side is not sensitive to touch, but the known disadvantages of touch such as scratches, electrostatic Charging, etc., caused by such rollers should be avoided.

The present invention has for its object that to further develop the deflection principle known from DE 35 12 316 such that even on a touch of the web can be dispensed with on its outer side, so that a completely non-contact web deflection on both sides he follows.

The solution to the problem of a two-sided contactless guiding and deflection of a moving web 1 is achieved according to the invention in that at the entrance and / or exit 2 or 3 of the deflection area a different pressure p, p _o connecting and the Moving web 1 leading flow channel 16 is arranged, the flow channel walls are formed by a defined flow guide body 5, 6, the side walls 7 of the chamber 8 and the moving web 1, so that a vacuum profile is built up along the flow channel during operation and web 1 separates areas 16, 17 of unequal pressure.

According to the present invention, sealing is conscious of the negative pressure space compared to the environment waived. The stabilization of web 1 in the input and / or Exit zones 2, 3 of the web deflection remain in advantageously fully preserved. By different constructive measures according to the invention succeed Incoming flows 12 and / or 13 so that the resulting Pressure distribution along this flow successful for a stable positioning of the web 1 on this is used in both positions. In comparison with the device described in DE 35 12 316 according to the invention the spaces of different pressures not sealed, so that a much higher air leakage is accepted in the vacuum chamber 18. Therefore but surprisingly becomes one on both sides the web 1 completely non-contact deflection of the Lane 1 reached.

1. Bahnstabilität muß auch bei zeitlichen Änderungen bzw. schlagartigen Pulsationen der Bahnspannung erhalten bleiben;

2. Ein eventuell auftretendes und störendes Flattern der Bahn, verursacht durch die an der äußeren Bahnoberfläche erfolgende Kanalströmung, muß vermieden werden;

3. Die Fähigkeit des Systems selbsttätig den Unterdruck in der Kammer aufzubauen und somit den normalen Betriebszustand herzustellen, wie dies etwa bei einer neuen Inbetriebnahme oder bei einer Wiederaufnahme des Betriebes wie z.B. nach einer Störung des Unterdrucksystems oder nach einem Bahnriß erforderlich wäre;

4. Die Intensität des Luftzustroms in die Kammer hinein und die dadurch verursachte eventuelle Beeinträchtigung einer auf der äußeren Bahnoberfläche befindlichen frischen, empfindlichen Beschichtung durch die von dieser Luftströmung verursachte Schubspannung an der Bahnoberfläche;

5. Der Energieaufwand für den Betrieb der Umlenkvorrichtung, der bei einer vollkommen berührungslosen Bahnumlenkung zu einem sehr wesentlichen Anteil von der Gestaltung der Strömungs-Leitkörper abhängt;

6. Zusätzliche Gesichtspunkte, die durch die Eigenschaften des Bahnmaterials, wie etwa Oberflächenstruktur, Porosität usw. gegeben sind und die sich bei unterschiedlichen Arten von Strömungskanälen verschieden auswirken können.

To achieve a contactless guidance of the moving and to be deflected web 1 in the input and output areas 2 and 3 of the web deflection, flow channels of different shapes are used according to the invention. The essential decision criteria when choosing the type, dimensioning the size and determining the position of the flow channels are:

1. Web stability must be maintained even with changes in time or sudden pulsations in the web tension;

2. A possibly occurring and disturbing flutter of the web, caused by the channel flow on the outer web surface, must be avoided;

3. The ability of the system to automatically build up the negative pressure in the chamber and thus restore the normal operating state, as would be required, for example, when starting up again or when restarting operation, for example after a fault in the negative pressure system or after a web break;

4. The intensity of the air flow into the chamber and the consequent possible impairment of a fresh, sensitive coating located on the outer web surface by the shear stress on the web surface caused by this air flow;

5. The energy expenditure for the operation of the deflection device, which in a completely contactless path deflection depends to a very large extent on the design of the flow guide bodies;

6. Additional aspects, which are given by the properties of the web material, such as surface structure, porosity, etc., and which can have different effects in different types of flow channels.

FIGUR 1

die schematische Darstellung der Bahnumlenkung mit einer kreiszylindrischen Umlenkfläche, einer Unterdruckkammer und Strömungskanälen am Ein- und Ausgang der Kammer mit der Ansicht X und dem Schnitt Y-Y;

FIGUR 2

(A) die schematische Darstellung der Positionierung eines Strömungs-Leitkörpers relativ zur Umlenkfläche einer Bahnumlenkung

(B) der Druckverlauf über der sich bewegenden Bahn

(C) der Verlauf des Differenzdruckes zwischen beiden Oberflächen der Bahn ;

FIGUR 3

die schematische Darstellung einer Bahnumlenkung sowie zwei Ausführungsbeispiele von Abstützflächen;

FIGUR 4

die schematische Darstellung der Spaltströmung

FIGUR 5

die schematische Darstellung der Spaltströmung unter geänderten Druckverhältnissen;

FIGUR 6

die schematische Darstellung einer Bahnumlenkung mit Hilfe eines feststehenden Kreisabschnittes mit seinen Strömungskanälen und einer Unterdruckkammer;

FIGUR 7

die schematische Darstellung der Bahnumlenkung nach Figur 6, jedoch mit einem Umlenkelement mit ortsveränderlichem Krümmungsradius;

FIGUR 8

verschiedene Ausführungsformen von Strömungs-Leitkörpern, nämlich:

eine konvexe (A), eine flache (B) und eine konkave (C) Form;

FIGUR 9

schematische Darstellung von Umlenkflächen, welche an beiden Rändern der Bahn unabhängig verstellbar (A) bzw. auswechselbar (B) sind;

FIGUR 10

alternative Gestaltungsmöglichkeiten der Umlenkelemente

(A) flache Umlenkelemente an beiden Rändern der Bahn

(B) labyrinthförmige Umlenkelemente an beiden Rändern der Bahn

(C) ein sich über die gesamte Bahnbreite erstreckendes labyrinthförmiges Umlenkelement

FIGUR 11

Wirkungsweise des Effekts der Bahnstabilisierung

FIGUR 12

Detaildarstellung eines labyrinthartigen Umlenkelements mit nach außen ansteigendem Radius

FIGUR 13

Effekt der Zentrierung der Bahn, der aus Umlenkelementen nach Fig. 12 resultiert

FIGUR 14

Darstellung eines sich über die Breite der Umlenkvorrichtung erstreckenden Umlenkelements mit nach außen ansteigendem Radius

FIGUR 15

labyrinthförmiges Umlenkelement mit alternativer Form der Rillen

FIGUR 16

schematische Darstellungen von veränderbaren Unterdruckkammern mit Strömungskanälen;

FIGUR 17

schematische Darstellung der Ausführungsform einer beweglichen Abstützfläche;

FIGUR 18

schematische Darstellung einer geringfügig schwenkbaren Abstützfläche für den Einsatz zur Seitenkantenregelung;

The invention is explained in more detail with reference to the drawings. Here show:

FIGURE 1

the schematic representation of the web deflection with a circular cylindrical deflection surface, a vacuum chamber and flow channels at the entrance and exit of the chamber with the view X and the section YY;

FIGURE 2

(A) the schematic representation of the positioning of a flow guide body relative to the deflection surface of a web deflection

(B) the pressure curve over the moving web

(C) the course of the differential pressure between both surfaces of the web;

FIGURE 3

the schematic representation of a web deflection and two embodiments of support surfaces;

FIGURE 4

the schematic representation of the gap flow

FIGURE 5

the schematic representation of the gap flow under changed pressure conditions;

FIGURE 6

the schematic representation of a web deflection using a fixed circular section with its flow channels and a vacuum chamber;

FIGURE 7

the schematic representation of the path deflection according to Figure 6, but with a deflection element with a variable radius of curvature;

FIGURE 8

different embodiments of flow guide bodies, namely:

a convex (A), a flat (B) and a concave (C) shape;

FIGURE 9

schematic representation of deflection surfaces which are independently adjustable (A) or exchangeable (B) on both edges of the web;

FIGURE 10

alternative design options for the deflection elements

(A) flat deflection elements on both edges of the web

(B) labyrinth-shaped deflection elements on both edges of the web

(C) a labyrinth-shaped deflection element that extends over the entire width of the web

FIGURE 11

Mode of action of the effect of web stabilization

FIGURE 12

Detailed representation of a labyrinth-like deflection element with an increasing radius

FIGURE 13

Effect of centering the web, which results from deflection elements according to FIG. 12

FIGURE 14

Representation of a deflecting element extending over the width of the deflecting device with an outwardly increasing radius

FIGURE 15

labyrinth-shaped deflection element with an alternative shape of the grooves

FIGURE 16

schematic representations of variable vacuum chambers with flow channels;

FIGURE 17

schematic representation of the embodiment of a movable support surface;

FIGURE 18

schematic representation of a slightly pivotable support surface for use for side edge control;

A targeted influence on the between the outer side of the web and the flow guide body taking place and by flow directed outside into the vacuum chamber in the meaning described above can be according to the invention achieve that these appropriately designed flow guide in a defined arrangement to the outer web surface to be installed. One very much effective and completely non-contact form of Path guidance can already be achieved in that plane plate-shaped flow directors 5 and 6 immediately be installed before or after the web deflection, as in Fig. 1 is shown schematically.

A detailed representation of the conditions in the input area 2 of the web deflection of the exemplary embodiment can be seen from FIG. 2. The flat flow guide body 5 forms an acute angle ω with the deflection surface 4 and thus with the web 1, which is here in a tangential arrangement to the deflection surface 4 and runs in a straight line before the deflection. A wedge-shaped channel 16 of rectangular cross-sectional shape thus arises between the flow guide body 5 and the outer web surface, in which a flow 12 directed into the chamber 8 (FIG. 1) takes place due to the pressure difference between the surroundings and the chamber. Due to the constant tapering of the flow cross-section between the flow guide body 5 and the web 1 in this channel, there is a constant acceleration of the air flow 12 and a corresponding continuous decrease in the air pressure on the outer side of the web 1 (see FIG. 2B) , while the inner web side is adjacent to the environment and is thus exposed to the ambient pressure p _o over the entire surface. The differently high pressure forces on both surfaces of the web on this channel section result in an outward differential pressure distribution p _o - p (α) on the web. Since the web is made of a flexible material, its shape within the channel section and in adjacent areas is largely determined by this pressure distribution along the channel resulting from the channel flow. The channel shape and thus the channel flow in turn strongly depend on the shape of this path section, because it represents a deformable wall of the channel 16. With a given shape and arrangement of the flow guide body 5 and with a certain negative pressure in the chamber 8, the web 1 then takes on a very specific shape in this area, which is due to the balance between the web tension forces T acting on it and the differential pressure forces p _o - p (α) is marked (Fig. 2C).

In the embodiment shown in Fig. 3, the two disk-shaped edge regions 21 of the rotatably mounted Roller 14 as deflection surfaces, while in between lying central cylinder section with a slightly smaller one Diameter serves as an emergency support.

In the area of the web deflection, a minimum value of the differential pressure p _o -p between the two surfaces of the web 1 should not be undershot at a specific web tension T and with a predetermined diameter of the circular-cylindrical deflection surfaces 21 if the web 1 does not rest on these two shoulders 21 shall be. If this is ensured, there is a gap s between the two surfaces 21 and the corresponding edge regions of the inner side of the web 1. Because of the pressure difference between the two base sides, an air flow 15 then takes place into the vacuum space 18, as can be seen from FIG. 1 . In order to maintain the vacuum, the amount of air entering the vacuum chamber 18 through this gap flow 15 must be constantly removed by the vacuum source U, the gap width s being adjustable by controlling its suction power.

With a closed and air-impermeable outer surface 9 of the body or the roller 14, the amount of air entering the chamber 8 through the above-mentioned gap flow 15 must be able to flow in the rectangular duct 17 between the inner surface of the web 1 and the outer surface 9 of the roller 14 (see 10 and 11 in Fig. 1 and Fig. 3), so that the ambient pressure p _o can be maintained on the concave base side. In order to ensure an unthrottled afterflow of air, the surface 9 of the emergency support can be made of a porous material (FIG. 3A) or provided with openings 20 (FIG. 3B) for the air entry so that the air flow from the environment to the concave surface of the web not only along the lateral surface 9 of the cylinder (10, 11), but also across it (19). For this, reference is made to FIG. 3. This measure allows the heel height between the deflecting surface 21 and the surface 9 of the emergency support to be kept small. Since the web 1 is not only supported on the central region 9 of the body 14 in the event of a malfunction but also partially rests on the two shoulders 21, this allows the mechanical load on the web 1 which arises when the web is emergency supported to be kept low. This is particularly important for sensitive web materials, because otherwise web 1 can tear due to the disproportionate load in the edge area. A low heel height is also an advantage if the normal operating status is to be restored from a standstill or a malfunction. A very strong buckling of the web in the middle area also makes it more difficult to build up the negative pressure in the chamber 8 and to establish the channel flows 12, 13 after a standstill.

If the middle lateral surface 9 of the body 14 is disruptive or if there is a system malfunction such as a failure of the vacuum source (U) can be largely excluded the middle portion of the body 14 may be omitted. In this case, only two deflection surfaces are in shape of rotatably mounted disks 21 in both edge areas web 1 as shown in Fig. 4B. The main advantage of using a swivel mounted roller 14 of FIG. 1 or also rotatable disk-shaped deflection elements 21 according to FIG. 4B Possibility of emergency support of the web 1 over its entire Web width in the case of a carrier roller 14 or over the Width of the deflection surfaces in the case of carrier disks 21. This helps the negative consequences of a system malfunction hold.

If there is a light contact of the outermost edges of the web 1 tolerated on rotatable deflection surfaces 21 of the roller 14 the gap flow 15 can be completely prevented be, so that correspondingly low energy consumption to maintain the negative pressure in the Chamber 8 becomes necessary. These relationships are in FIG. 5 shown.

To avoid grinding the web on deflection surfaces, in this case it must be ensured that the Deflection surfaces 21 identical with a peripheral speed rotate at the web speed. This can be done with With the help of frictional forces, through the web 1 itself or done by an external drive.

In the event of a complete lift of the web from the Deflection surfaces 21 can also be fixed Surfaces are designed and no longer need to consist of a closed cylinder 14. You can therefore on a cylinder cutout 22 in the deflection area can be limited, as shown in Fig. 6. Because of the Lack of a rotational movement can be fixed Deflection surfaces also have a shape other than a circular cylinder to have. So you can e.g. from an elliptical cylinder surface 23, as shown in Fig. 7 exist. It can be other cylindrical, not shown Use shapes here.

For a complete wrap through the web 1 To ensure, however, the contour must cover the length be convex. This freedom gives the opportunity the shape of the deflection at different angular positions To design α individually, see Fig. 7. Es all that needs to be done is to ensure that the transition between Arch sections with different radii of curvature takes place continuously and from the web tension permissible minimum radius of curvature at no point in the Contour of the deflection is undershot.

Thus, the entry and exit areas of the redirection be designed primarily with regard to the channel flow, while optimizing the rest of the areas after others Aspects such as the desired column width on both edges of the document.

The contour can also consist of a curve in which the local radius of curvature in a given manner (e.g. after a mathematical dependency) as a function the angular coordinate α of the deflection results. The permanently installed Deflection elements do not necessarily have to consist of solid cylinders or their segments. You can also by bending a strip-like material can be made into the desired curved shape, thereby reducing manufacturing costs.

The set forth in connection with the embodiment in Fig. 3 Considerations regarding the design options the middle surface of the emergency support or its total elimination (Fig. 3 or Fig. 4 and Fig. 5) of course apply analogously also for the two shown in FIGS. 6 and 7 But also examples for each any form of deflection and not shown here Support surfaces.

The contour of the flow guide body facing the path 5, 6 may be flat or along the flow channel 16 have an arbitrarily curved shape. To the context between the shape of the flow guide and the resulting shape of the track section in the channel 16, these relationships are shown in FIG. 8 in each case for a convex (Fig. 8A), a flat (Fig. 8B) and a concave (FIG. 8C) shape of the flow guide body 24, 25, or 26 represented qualitatively.

The convex shape of the flow guide body 24 is through the highest rate of cross-sectional narrowing in channel 16 featured. The vacuum distribution is predominant determined by the end region of the channel flow. Accordingly lane 1 is still approximate in the initial section straight and only becomes strong in the end area Flow guide body 24 deformed. The danger of unintentional Touch the flow guide body through the web therefore only exists in this end area.

With a flat flow guide body 25 according to FIG. 8B the contribution of the last channel section is no longer so dominant and the middle section of the canal also performs an essential part to build up the negative pressure forces.

In the case of a concave flow guide body 26, there is still one larger section involved in building up the negative pressure. The forms of the vacuum curve are correspondingly flatter and the train.

Because all three embodiments of the flow guide are characterized by certain advantages and disadvantages, should when deciding on the choice of the appropriate Shape of the flow guide body in each specific case respective operating environment are considered in more detail.

A flow guide can be used to achieve an optimal effect also from a certain combination of the three Forms A, B and C can be put together. The flow guide in this case consists of a sequential Arrangement of several sections different Shape and curvature.

The flow guide body can be in any position Holes or slots of any shape and size or the channel surface can be whole or consist in sections of an air-permeable material, a deliberately wanted inflow of outside air in to enable the negative pressure area in the air duct 16. This can e.g. make sense in connection with a concave Flow guide body to a total suction of the web to exclude the flow guide body 26.

However, it can pass through such openings in the flow guide body actively pumped air into the flow channel 16 to increase the intensity of the channel flow and consciously control them within certain limits. Such one The procedure is based on air nozzles for stabilizing the web known based on the principle of building a negative pressure between the web and one close to its surface Nozzle emerging from the nozzle tangentially Air flow based.

To ensure that the channel flow is as free of eddies as possible 12, 13 to enable the vacuum chamber 18 of the chamber 8 can the flow guide body 5, 6 inside the box be continued, so that the cross-sectional area of the Channel 16 rises again. This can be different Form the flow guide in the inlet area with also different shapes combined in the outlet area become. In this regard, with the help of different, generally known measures, as by making holes in the outlet area of the Flow guide body the gentle adjustment of the pressure the channel flow to the level in the vacuum chamber 8 can be realized.

The channel flow is in the case of a longitudinal movement Trajectory also a flow due to the air boundary layer superimposed on the moving web surface. The intensity this boundary layer flow increases with the web speed on. This flow is at the entrance of lane 1 in the deflection chamber 8 is also directed into the interior of the chamber and is therefore superimposed by the vacuum in the chamber 8 caused channel flow 12. At The boundary layer flow is the exit of the web 1 from the chamber 8 the channel flow 13 directed in the opposite direction. At high web speeds, the entry and Outlet area 2 or 3 different flow conditions exist in these channels so that to take into account of these relationships individually different Shapes or positions of the flow guide bodies required are.

The shape of the profile of the flow guide body can vary if necessary also as a function of the coordinate across Change the direction of movement of the path. This can e.g. at larger web widths and high web speeds be useful if the boundary layer flow in the middle Area of the web looks much different than in the through strong vertebral detachment marked edge area. But this can also be due to an air permeability of the Web material or its possible location dependency in Direction of web width may be advantageous. Also one Change in thickness or specific weight of the material can be factors in such an approach make it seem sensible.

The flow guide body can be straight in the transverse direction or be curved. By a curved one Shape can be imposed on the web in a slightly curved shape become. By applying a curvature The conditions before and / or after the deflection chamber in the chamber 8 can be controlled within certain limits. Flow guide bodies curved in the transverse direction can can also be used when locally different Conditions on the flow guide body from certain Considerations are considered beneficial.

In an advantageous embodiment, the deflection surfaces 27, 28 independently on both edges of the web 3 adjustable so that it is parallel to the axis of movement Web width positioned at any distance from each other can be. For this, reference is made to FIG. 9A.

The deflection device is in another variant of the Invention designed so that it with 29 different deflection surfaces Shape and / or position can, as can be seen from FIG. 9B.

The flow guide in the entrance and exit areas the redirection are either appropriate dimensioned the maximum web width and protrude narrower materials beyond the web width or they too are made easily interchangeable, so that different sized and / or shaped and / or positioned flow guide bodies in connection with different web widths can.

In a further advantageous embodiment the deflection elements 33, 34 from a number of smaller ones Surfaces and the grooves in between, like from 10B can be seen. Through the alternating achieved thereby Widening and narrowing of the gap between the Inner surface of the web and the deflecting element, the simple predominantly one-dimensional gap flow 32 flat deflecting body 30, 31 (Fig. 10A) replaced by a more complicated flow 35 (Fig. 10B). That kind of The design of a sealing gap is called a labyrinth seal known and allows a much more efficient Sealing the vacuum chamber 18 against the Environment than this with a simple gap more constant Cross-sectional area (Fig. 10A) is possible. Consequently can with the same power of the vacuum source larger gap widths s between the web and the deflection surfaces to reach. The labyrinthine Deflection surface on the two edge areas of the web restrict (Fig. 10B) but also to the total width of the web (Fig. 10C). The schematic in Fig. 9 shown adaptation of the equipment to the width of the respective path can be used when using deflection surfaces extend over the entire width of the deflection device (36), omitted if this deflection element is wide it is enough to cover all possible web widths. This is a very important benefit in practice, though Web materials with widely differing widths for Come into play.

The better seal prevents labyrithic Design of the deflecting element that at one too strong lifting of the web from the deflection surface - like this e.g. if the web tension suddenly drops The vacuum in room 18 can suddenly occur collapses. This helps the system instabilities drastically reduce that would normally arise if the air leakage fluctuates greatly in time is subjected and the vacuum source is too sluggish To follow fluctuations.

Put in connection with the present application these advantages of a labyrinth-like deflection element however, only welcome side effects. The real one However, the purpose of this design form is with it associated stabilizing effect, which makes it possible to prevent unwanted lateral running of the web. With a completely contactless deflection device are usually just forces perpendicular to the web surface generated that arise during the web deflection Should compensate web forces. Tangential to Forces directed at the surface of the web are however to be secured the lateral position of the web is required and these are mostly not available.

The stabilizing effect of a labyrinth-like deflection surface in this case arises at the point of entry of the Leakage air in the vacuum chamber (18) and this can be done explain with reference to FIG. 11. Here are three different ones Lateral positions of one edge of the web (1) shown. The ones on the last one below the track (1) Elevation 37 of the deflecting element 34 flowing past Air 35 relaxes in the adjacent groove 38, which is only partially covered by the train, and arrives after a change of direction in the vacuum chamber 18. This creates a groove 38 in the interior of the Vacuum chamber 18 directed air jet L. With a side Displacement of the path as shown in FIG. 11B, the available for this air jet narrows Width at the narrow point 36. The speed and thus the energy of the air jet L increases. The train calls an increasing one as it moves further to the side Narrowing of the narrowest point 36 and must therefore move through a strong air jet L. Of the Impulse of the air jet L sets such a lateral one Resistance to the movement of the web and exercises therefore one opposite to the lateral path movement Power out. This effect remains until the groove 38 is completely covered by lane 1 and the edge of the Bahn reached the next elevation.

An additional stabilizing effect can be achieved if the elevations increase towards the outside, so that the transition from one survey to another with a corresponding lifting of the web by the dimension Δh (Fig. 12) is connected. Because the web is under a web tension stands for this resulting increase in Radius of curvature of the path an energy can be spent. As a result, the lateral displacement of the web a resistance from a position P1 to a new position P2 is opposed. With a constant increase in The height of the elevations form a shell contour in the the web is positioned centrally (Fig. 13A). If there is any lateral shift as shown schematically in Fig. 13B shown, the path inevitably takes an oblique position in this bowl because of a movement of the web the middle layer out then always with their lifting on one edge and a corresponding drop on the other Edge is connected. With such an oblique orientation Railway arise in it due to the railway tension from high lateral forces F directed to the low edge the web endeavors to return to its original central position bring. This additional stabilizing effects of a labyrinthine Deflection elements with a shell contour reinforce the effect of a labyrinth structure explained above with a uniform survey height.

In Fig. 14 is an over the width of the deflection device extending deflecting element 41 with an outwardly rising one Radius of the strip-shaped deflection surfaces shown.

The central positioning of the web (1), which is at Use of deflection elements with an outward slope Radius of the strip-shaped deflection surfaces results can be used to actively influence the lateral web position are used when the deflecting elements 39 and 40 or the deflection element 41 transversely to the web running direction can be moved. If a lateral is found The course of the web (1) by means of a sensor is used for this the deflection elements 39 and 40 or the deflection element 41 according to a control algorithm and by means of a Mechanism for parallel shift in a new transverse one Position. The explained with reference to FIG. 13 Centering forces F, which arise from the resulting asymmetrical Arrangement of the deflection elements relative to the web (1) result in correcting the lateral web position used. Can achieve the same effect of course, instead of the deflection elements, the entire one Deflection device can be moved in the transverse direction. At Use of two deflection elements 39, 40 is, however the solution to the problem by simply moving the Deflection elements make more sense because the same displacement mechanism also for individual repositioning of the two deflection elements in order to adapt to different ones Web widths (according to FIG. 9A) can be used can.

The number of surveys and the width of each survey can individually adapt to the given circumstances be adjusted. In this context, they can all have a uniform width but also individually be dimensioned. Even in the circumferential direction do not necessarily need the edges of these elevations to be straight. Rather, you can create a wavy, have sawtooth-like or other shapes. This Statements apply mutatis mutandis to grooves that refer to their width, their depth, but especially the contour of theirs Cross-section can be designed arbitrarily. In this Context can be optimally coordinated this parameter the properties of the air jet L im Be consciously influenced with regard to their stabilizing effect. Through a more aerodynamically favorable design the contour of the grooves, e.g. by choosing a curved one Geometry 42 (Fig. 15) instead of an angular shape for example, ensured that the energy of the air steel L largely preserved when the direction changes in the groove remains and is not reduced by extreme vortex formation becomes.

In a further advantageous embodiment, the flow guide bodies are designed to be flexible, regardless of their embodiment, in such a way that their distance d _min and their arrangement angle α and angular position ω with respect to the deflection element can be changed precisely and reproducibly, see FIG. Fig. 2. Thus, the same deflection device can be used optimally in connection with different web materials and operating conditions.

In a further advantageous embodiment the flow guide body than in the circumferential direction of the Wrapping made slidable. If doing so by Construction as schematically shown in Fig. 16 it is ensured that despite the adjustment of the flow guide sealing the room 18 under Keeping negative pressure in relation to the environment arises a possibility of flexibly changing the path configuration, as also from FIG. 16 for a 180 ° or 90 ° path deflection can be seen. Figures A, B and C show different displacement mechanisms.

By means of a movable support surface 43, as shown, for example, in FIG. 17, it can be achieved that in the event of a malfunction or an intentional shutdown of the production system, the emergency support is automatically moved radially outwards and thus assumes a new position approximately at the deflection surfaces 44. In the embodiment of such a device shown schematically here, the differential pressure between the two surfaces of the web 1 is used as the reference variable for controlling a pneumatic drive system 45. After a corresponding amplification of the differential pressure p ₀ - p with factor K, the pressure is set K x (p 0 - p) by means of a pneumatic cylinder ensure that in normal operating conditions the emergency support is kept at a certain distance from the web despite the action of a compression spring 46 (state A). In the event of a deliberate or fault-related drop in this differential pressure, the spring 46 presses the emergency support into a new position at the same height as the deflecting surfaces 44 (state B).

As in the case of a wrapped wave, the Lane 1 also with a deflection device of the one described here Art (Fig. 18) in the wrapping of the deflection surfaces 47 aligned perpendicular to their axis 49. This Behavior can be used to the side position the web 1 actively through a side edge control influence. For this purpose, the deflection device around the Axis 48 perpendicular to the cylinder axis of the deflection surfaces 47 swivel design. The current location of lane 1 will detected by a sensor and a deviation from the predetermined target position is determined by means of a minor Corrected swivel movement by angle  as from 18 can be seen. The deflection device at the same time for the change of direction of lane 1 and for the Function of the side edge control can be used.

Claims (10)

1. Device for changing the direction of a moving web (1) that, in the area of direction change, separates an inner zone associated with the inner web surface from an outer zone associated with the outer web surface, where the outer zone is formed by a chamber (8,18) connected to a negative pressure source and the inner zone is at atmospheric pressure. In both of the edge regions of the web (1) a guide surface (21) is positioned in a way that, due to the pressure difference between the two zones, a gap s is formed between the web edge and guide surface (21). The device is characterized by the air channel (16) that is positioned at the entrance and/or exit of the turn region (2 and 3 respectively), the walls of which channel consist of a baffle (5, 6) with a defined shape, the side walls (7) of the chamber (8) and the moving web (1), and which connects the zones of different pressure with each other and guides the moving web (1) in a way that during operation a negative pressure profile along the channel is established and the web (1) separates the zones (16 and 17) of different pressure from each other.
2. Device according to claim 1 characterized in that the guide surfaces (21) are the rims of two discs which are positioned laterally at each end of a convex cylindrical body (14), the discs having a radius larger than that of the cylindrical body (14).
3. Device according to claim 1 or 2 characterized in that the body (14) is designed to be porous or has holes (20) which have various sizes and are variously distributed over the periphery of the body (14).
4. Device according to any of the foregoing claims characterized in that the guide elements are formed from a number of parallel ridges and the grooves between them (33, 34).
5. Device according to claim 4 characterized in that both guide elements 33 and 34 are combined to one common guide element 36 extending over the total width of the device.
6. Device according to claim 4 or 5 characterized in that the radius of the ridges of the guide elements 36 or 33 and 34 respectively increases from the middle to the edges of the web turn device ( 41 or 39 and 40 respectively).
7. Device according to claim 6 characterized in that the guide elements 41 or 39 and 40 respectively are designed to be movable perpendicular to the running direction of the web.
8. Device according to claim 7 characterized in that the movement of the guide surfaces 41 or 39 and 40 respectively is designed to be controllable by means of sensors.
9. Device according to any of the foregoing claims characterized in that the baffle (5,6) is designed as a flat plate installed in an adjustable arrangement with respect to the web (1).
10. Device according to any of the foregoing claims characterized in that the support surface (43) is designed to be movable.

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