EP2016225B1 - Apparatus for forming at least one extended nip - Google Patents

Abstract

Apparatus for forming at least one extended nip between a backing roll and a shoe roll for treating a material web, wherein the shoe roll has a stationary carrier and a flexible roll cover which can rotate around the carrier and is supported in the region of the extended nip on a shoe which is guided on the carrier, forms a pressing section and has an active shoe width, and the shoe can be pressed against the backing roll via at least one hydraulic element, wherein the at least one hydraulic element is configured on the carrier as a cylinder/piston unit, on which the shoe is mounted in a floating manner, wherein the hydraulic element (7) has, as piston, a sealing member (8) having at least one hydrostatic pressure chamber (9) which has a raised border all the way around, is open towards the shoe (6), can be loaded via at least one channel (10) with the working force of the pressure medium in a cylinder chamber (11) as supporting force, and has a supporting force in a region on the outlet side displaced towards a centre (Ms) of the active shoe width (SBw), and at least two further edge chambers (12, 13) are provided which are open towards the shoe (6) at a spacing from the pressure chamber (9), have raised borders all the way around and can be supplied as hydrostatic bearings with a pressure medium via throttle points (14, 15).

Description

The invention relates to a device for forming at least one extended nip between a mating roll and a shoe roll for treating a material web, in particular a paper web, board web or tissue web, according to the preamble of claim 1.

A device according to the preamble of claim 1 is known from DE 100 36 674 A ,

Out DE 195 15 832 C1 is a shoe press roll for a paper machine is known, which forms a press nip with a counter-roller through which a guided over the shoe press roll press jacket rotates together with a paper web. The shoe press roll comprises a press shoe, which can be pressed against the counter roll via at least one hydraulic element. The at least one hydraulic element is formed as a cylinder / piston unit between a stationary support body and the press shoe and comprises a first, acted upon by hydraulic pressure cylinder chamber, via a throttle point with a hydrostatic bearing pocket which is open toward the press shoe is connected, which rests against the press shoe at the edge with a sealing surface in which a sealing ring is held. The disadvantage here is that when clogging the throttle, the oil supply of the hydrostatic bearing pocket is lost. The piston is then supported on the shoe via the sealing ring, so that the full pressure force acting on the piston is transmitted via the sealing ring to the shoe. The high pressure forces inevitably lead to destruction of the sealing ring and damage to the press shoe. The susceptibility to wear of such a shoe press roll with a hydrostatic piston therefore increases their cost significantly.

The object of the invention is therefore to provide a device for forming at least one extended nip, which is simple and inexpensive to manufacture and in operation, while ensuring a high quality of the web to be treated.

This object is solved by the features of the characterizing part of claim 1.

In this way, a device is provided for forming at least one extended nip, in which the power is transmitted to the shoe by means of the column of the pressure medium, in particular oil column, within the hydraulic element. This precludes undefined friction of the hydraulic elements on the shoe and increased wear. At the same time, the column of the pressure medium allows the displacement of the maximum supporting force into a region of an effective shoe width on the outlet side adjacent to the middle of the effective shoe width. The pressure pressure profile in the press nip, in particular the pressure increase, can therefore be influenced by the working force in the hydraulic element. As a result, the compression pressure profile is no longer dictated solely by the shoe designs, in particular the shoe shape. Finally, regardless of the operating state of the hydraulic elements, the shoe is mounted on an oil film which the marginal chambers provide as hydrostatic spacers. A wear-free operation is characterized ensures that the marginal chambers for a hydrostatic system with a virtually frictionless floating storage of the shoe on the hydraulic elements care, and separate from their labor. The marginal chambers allow a stabilizing effect that can be chosen as large as possible. This improves the positioning of the shoe, in particular because this positioning acts independently of the center of gravity of the surface pressure of the effective supporting force outside the effective shoe center.

In thermal deformations of the shoe or mechanical deformation of the wearer, it can thus come to a deformation compensation between the wearer and the shoe, without forcing forces between the shoe and the hydraulic elements can occur. Since the hydraulic elements can absorb a tendency in the machine direction and transversely thereto, the seal member always remains flat on shoe bottom rest in shoe shifts and Achsverformungen so that it can not come in the operating condition to increased leakage and loss of hydrostatic bearing function.

Preferably, a plurality of hydraulic elements are arranged distributed over a shoe length, which are combined in zones or individually controllable or regulated. A uniform grid of pressure ranges is adjustable. Thus, local deformations of the shoe between the individual hydraulic elements can be minimized. Hydraulic elements can be individually controlled at least at one end of a shoe length in the cross-machine direction in order to individually solve edge problems.

The at least two marginal chambers may be arranged symmetrically to the center of the sealing member of a hydraulic element or symmetrically to the center of an entire shoe width for an adjustment of the shoe. Alternatively, the at least two edge chambers may be arranged asymmetrically to the center of the sealing member of a hydraulic element. The arrangement of the edge chambers can be selected depending on the shoe design in terms of length and shape in order to achieve the widest possible circulation of the shoe. Of the Press pressure curve in a main press zone can be so detached from storage problems. Number and shape of marginal chambers can be selected.

The cross section of the pressure chamber is preferably equal to or only slightly smaller or larger than the cross section of the cylinder chamber. The leading to the pressure chamber channels are preferably throttle free, so that the working pressure is substantially equal to the supporting force of the hydraulic element.

Preferably, at least two partial pressure regions are arranged one behind the other in the machine direction within a hydraulic element in order to be able to influence the compression pressure profile in the extended nip. Preferably, the at least two partial pressure regions have different pressure forces, in which case the outlet-side partial pressure region has the pressure force of the maximum supporting force.

The hydraulic element may preferably be biased relative to the shoe by means of a spring or piston element.

Preferably, a stroke limitation of the shoe is provided for a change of the roll mantle to avoid falling out of the shoe after nip opening when the shoe is down. To limit the stroke head bolts may be provided, which may also be biased by compression springs. A quick release is thereby possible, in which the hydraulic element springs back from the shoe.

The sealing member may comprise a support plate for the shoe, which is designed so stiff that the deformations of the support plate under load are small. Placing hydraulic elements with such a sealing member side by side, the shoe can be kept very flexible in its longitudinal direction, ie in the cross machine direction. For example, flat shoes and / or shoes made of plastic or other materials with a low modulus, such as aluminum or magnesium alloys, can be used. That way it is possible, too To generate small line forces enough corrections in the cross machine direction. This profiling is particularly important in shoe rolls for tissue machines in the areas of the roll edges.

The hydraulic element may have a sealing member, which has a collar at its end remote from the shoe, which can dip into an annular groove in the cylinder chamber at the lowering. The oil to be displaced from the annular groove leads to a cushioning effect to a cushioning.

The shoe is preferably held in place for positioning over individual fasteners in the machine direction. Preferably, the individual attachment in the quarter points based on the length of the shoe.

Further embodiments of the invention are described in the following description and the dependent claims.

• Fig. 1 zeigt schematisch im Längsschnitt eine Vorrichtung zum Bilden eines Langspalts gemäß einem ersten Ausführungsbeispiel,
• Fig. 2a zeigt schematisch in einem Querschnitt die Schuhwalze gemäß Fig. 1,
• Fig. 2b zeigt schematisch in einem Querschnitt eine Schuhwalze gemäß einem zweiten Ausführungsbeispiel,
• Fig. 2c zeigt schematisch in einem Querschnitt eine Schuhwalze gemäß einem dritten Ausführungsbeispiel,
• Fig. 2d zeigt schematisch in einem Querschnitt eine Schuhwalze gemäß einem vierten Ausführungsbeispiel,
• Fig. 2e zeigt schematisch in einem Querschnitt eine Schuhwalze gemäß einem fünften Ausführungsbeispiel,
• Fig. 2f zeigt schematisch in einem Querschnitt eine Schuhwalze gemäß einem sechsten Ausführungsbeispiel,
• Fig. 2g zeigt schematisch in einem Querschnitt eine Schuhwalze gemäß einem siebten Ausführungsbeispiel,
• Fig. 2h zeigt schematisch in einem Querschnitt eine Schuhwalze gemäß einem achten Ausführungsbeispiel,
• Fig. 2i zeigt schematisch in einem Querschnitt eine Schuhwalze gemäß einem neunten Ausführungsbeispiel,
• Fig. 3a zeigt schematisch einen Schnitt nach A-A der Fig. 2a,
• Fig. 3b zeigt schematisch einen Schnitt nach A-A der Fig. 2e,
• Fig. 3c zeigt schematisch einen Schnitt nach A-A der Fig. 2f,
• Fig. 3d zeigt schematisch einen Schnitt nach A-A der Fig. 2g,
• Fig. 4 zeigt schematisch eine Draufsicht eines Schuhs einer Schuhwalze gemäß Fig.1,
• Fig. 5 bis Fig. 8 zeigen jeweils in schematischer Draufsicht Anordnungen von Hydraulikelementen entlang einer Schuhlänge.

The invention will be explained in more detail with reference to the embodiments illustrated in the accompanying drawings.

• Fig. 1 shows schematically in longitudinal section a device for forming an extended nip according to a first embodiment,
• Fig. 2a shows schematically in a cross section the shoe roll according to Fig. 1 .
• Fig. 2b shows schematically in a cross section a shoe roll according to a second embodiment,
• Fig. 2c shows schematically in a cross section a shoe roll according to a third embodiment,
• Fig. 2d shows schematically in a cross section a shoe roll according to a fourth embodiment,
• Fig. 2e shows schematically in a cross section a shoe roll according to a fifth embodiment,
• Fig. 2f shows schematically in a cross section a shoe roll according to a sixth embodiment,
• Fig. 2g shows schematically in a cross section a shoe roll according to a seventh embodiment,
• Fig. 2h shows schematically in a cross section a shoe roll according to an eighth embodiment,
• Fig. 2i shows schematically in a cross section a shoe roll according to a ninth embodiment,
• Fig. 3a schematically shows a section according to AA Fig. 2a .
• Fig. 3b schematically shows a section according to AA Fig. 2e .
• Fig. 3c schematically shows a section according to AA Fig. 2f .
• Fig. 3d schematically shows a section according to AA Fig. 2g .
• Fig. 4 schematically shows a plan view of a shoe of a shoe roll according to Fig.1 .
• Fig. 5 to Fig. 8 each show in schematic plan view arrangements of hydraulic elements along a shoe length.

The invention relates to a device for forming at least one extended nip between a backing roll 1 and a shoe roll 2 for treating a web. The shoe roll 2 has a fixed support 3 and a rotatable about the support 3, flexible roll shell 4. The roll shell 4 is supported in the region of the extended nip 5 on a shoe 6 guided on the support 3, forming a pressure section and having an effective shoe width SBw. The shoe 6 can be pressed against the counter-roller 1 via at least one hydraulic element 7, wherein the at least one hydraulic element 7 is designed as a cylinder / piston unit on the carrier 3, on which the shoe 6 is mounted in a floating manner.

As a piston, the hydraulic element 7 has a sealing member 8 with at least one hydrostatic pressure chamber 9 which is open towards the shoe 6 and surrounded by a ring, which has at least one channel 10 with the working force of the pressure medium in one Cylinder chamber 11 can be acted upon as a supporting force. The pressure chamber 9 has a supporting force in a region of an effective shoe width SBw on the outlet side displaced to the center Ms of the effective shoe width SBw.

At least two further marginal chambers 12, 13 which are open at a distance from the pressure chamber 9 to the shoe 6 and are surrounded all around, are provided which can be supplied as hydrostatic bearings via throttle points 14, 15 with a pressure medium.

How out Fig. 1 can be seen, preferably a plurality of hydraulic elements 7 are arranged distributed over a shoe length, which are summarized in zones controllable. For this purpose, for example, all central hydraulic elements 7 are connected to a supply line 16 for pressure medium, while at least end-mounted hydraulic elements 17, 18 are individually controllable via separate supply lines 19, 20. All supply lines 16, 19, 20 are preferably connected to a central supply line 21 for pressure medium , The central supply line 21 is fed from a reservoir 22 for pressure medium, wherein a pump 23 and a pressure regulator 24 are used to set a working pressure. In order to be able to apply a lower working pressure to end-side hydraulic elements 17, 18, pressure-reducing valves 25, 26 are provided in the supply lines 19, 20. In the central supply line 21 finally processing equipment, such as a filter 27 may be installed.

The counter roll 1 and the shoe roll 2 according to Fig. 1 can be stored in a known manner in a stand, not shown, and optionally pressed against each other by suitable load devices, not shown. The counter-roller 1 is preferably supported by roller bearings 28 provided on roll necks. The shoe roll 2 rests with fixed roll pins 30 extending from the carrier 3 in the stand. The roll shell 4 has end portions which are fastened to end walls 31 rotatably mounted on the carrier 3 are. The counter roll 1 is here preferably a conventional solid roller. Alternatively, the backing roll may also be formed as a shoe roll or as a bending roll.

In the Fig. 1 illustrated mating roll 1 and shoe roll 2 may form, for example, a shoe press for squeezing water from a web or a shoe calender for smoothing a web. In addition, the two rollers can also form part of a multi-rolling arrangement, so be combined for example in a roll stack with other rollers.

Fig. 2a shows a first embodiment of a shoe roll 2 for the inventive device for forming at least one extended nip 5. The hydraulic element 7 then comprises a sealing member 8 which is slidably guided in a blind bore 32 at the top of the carrier 3 and with a correspondingly shaped end face sealingly against the Bottom 33 of the shoe 6 rests. Preferably, the end face of the sealing member 8 is formed flat. The blind bore 32 is connected via a connecting line 34 with a supply line 16, 19, 20 and via this with the central supply line 21 and the control means 24, 25, 26. In the open against the bottom 33 of the shoe 6 pressure chamber 9 in the interior of the sealing member 8 can be constructed in this way a compressive force.

The sealing member 8 includes a piston or stamp-like housing 35 which sits with clearance in the cylinder blind bore 32. A circumferential piston-ring-like seal 36 provides a seal in the lifting movement of the sealing member 8 in the axial direction of the blind bore 32. At the bottom or rear of the sealing member 8 and a bottom 37 of the blind bore 32, the cylinder chamber 11 is formed, which via the supply line 34 with Pressure fluid can be acted upon. At the upper end, the sealing member 8 has a closed peripheral edge 38 which surrounds the pressure chamber 9 preferably circular. The peripheral edge 38 forms a boundary surface of the sealing member 8 relative to the underside 33 of the shoe 6. A contact surface on the underside 33 of the shoe forms the column of pressure fluid, which is present in the pressure pocket 9.

The sealing member 8 has at least one between the pressure chamber 9 and the cylinder chamber 11 extending channel 10 with a large cross section. Preferably, a plurality of channels 10, in particular 4 channels, are provided. Due to the large cross section of the channel 10 and the channels 10, the pressure in the cylinder chamber 11 is also in the pressure chamber 9 and acts in its cross section against the bottom 33 of the shoe. This force can be formed higher or lower by changing the cross-sectional area than in the cylinder chamber 11. The cross-section of the pressure chamber 9 is for example up to 5% smaller or larger than the cross-section of the blind bore 32, which is preferably a cylinder blind bore.

The marginal chambers 12, 13 are each connected to the cylinder chamber 11 via a throttling channel 39, 40. As a result of the throttling, a supporting liquid film, which supports the sealing member 8 against the underside 33 of the shoe 6, adjoins the edge chambers 12, 13, which form part of the end face of the sealing member 8. The edge chambers 12, 13 are bounded by an edge 42 which forms a portion of the end face of the sealing member 8 as well as the edge 38 of the pressure chamber. 9

The according to Fig. 3a existing four evenly distributed over the circumference edge chambers 12, 13; 12 ', 13' are separated from each other and are separately throttled supplied with pressurized liquid, so that a supporting liquid film of a predetermined thickness at circumferentially distributed locations is present and the entire seal member 8 is supported in a stable manner on a liquid film without it may come to a contact between the edge 38 and the lower portion 33 of the shoe 6.

The number and shape of the marginal chambers 12, 13; 12 ', 13' is selectable without losing its function as a hydrostatic spacer. According to Fig. 1 four circumferentially distributed edge chambers are provided. Alternatively, at least one respective peripheral chamber 12, 13 is arranged on the inlet and outlet side of each pressure chamber 9. Inlet and outlet side refers to the machine direction, which is indicated by the arrow L in Fig. 2a is specified.

As Fig. 2a shows, the pressure chamber 9 is offset from the effective shoe width SBw outlet side. The effective shoe width SBw is used here, since this is the effective pressure zone of the extended nip 5 for the treatment of a web. The shoe 6 may have on and / or outlet side inlet and outlet zones, which may have no influence on this pressure zone.

The pressure curve in the pressure zone of the extended nip 5 along the effective shoe width SBw is determined by the pressure chamber 9 and the oil column set in this pressure chamber 9, which transfers the working force from the cylinder chamber 11 to the underside 33 of the shoe 6 as a supporting force. According to Fig. 1 a uniform pressure chamber 9 is provided. The maximum supporting force is therefore on the entire cross-sectional area of the pressure chamber 9, whose center MD is offset from the middle of the effective width Ms shoe width SBw outlet side. The center M _{D of} the pressure chamber 9 preferably also corresponds to the center of the sealing member 8.

The at least two edge chambers 12, 13 are arranged symmetrically to the center MD of the sealing member 8.

The housing 35 of the sealing member 8 is preferably T-shaped, whereby the end face of the sealing member 8 provides a support member which may extend substantially across the width of the shoe 6 in the region of its effective shoe width SBw. A spacing 41 between an edge chamber 12, 13 and the edge 38 of the pressure chamber 9 can be selected as a function of the total shoe width on which the underside 33 extends. The Shoe widths can vary between 10 and 80 cm. Consequently, the at least two marginal chambers can also be arranged symmetrically with respect to a center of an entire shoe width. For calendering, the shoe widths can also vary between 1 and 10 cm.

The marginal chambers 12, 13; 12 ', 13' are according to Fig. 2a, 3a preferably designed round. Alternatively, the marginal chambers may be formed as arcuate pockets.

The sealing member 8 is finally arranged spring biased by a spring element 43 against the shoe 6.

According to a second in Fig. 2b illustrated embodiment of a shoe roll 2, the sealing member 8 via an inner support piston 44 against the shoe 6 can be prestressed. The at least two marginal chambers 12, 13 are then preferably connected via the throttle points 14, 15 with a formed inside the seal member 8 inner cylinder chamber 45 which is separated from the cylinder chamber 11 and provided with its own supply line 46. For sealing against the cylinder chamber 11 is preferably a piston-ring-like seal 47th

Incidentally, the above statements apply to the first embodiment accordingly.

According to a third in Fig. 2c illustrated embodiment of a shoe roll 2, the sealing member 8 stops 48 to a stroke limit of the sealing member 8 in the direction of shoe 6. The stops 48 are formed here by headed bolts 49, which are fixed to the carrier 3 and project into a guide bore 50 of the sealing member 8. Incidentally, the comments on the second embodiment apply accordingly. The same applies to the fourth embodiment in conjunction with the first embodiment. According to a fifth in Fig. 2e illustrated embodiment, the head bolts 49 carry according to the third embodiment each have a spring element 51 for a spring bias against the respective stop 48. Preferably, the stops 48 are provided only at the two in a cross-machine direction sealing ends 8 and / or their neighboring elements, so for example in the hydraulic elements 17, 18 according to Fig.1 ,

According to a sixth in Fig. 2f and Fig. 3c illustrated embodiment, at least one edge chamber 12 on the outlet side and an edge chamber 13 is arranged on the inlet side. In the machine direction, the inlet-side edge chamber 13 is arranged at a greater distance 41.1 to the pressure chamber 9 than the outlet side arranged edge chamber 12, which is arranged at a smaller distance 41.2 to the pressure chamber 9. An asymmetrical T-shaped configuration of the housing 35 of the sealing member 8 may result. Incidentally, the comments on the fifth embodiment apply accordingly.

According to a seventh in Fig. 2g illustrated embodiment, the pressure chamber 9 is segmented. The pressure chamber 9 is then composed of a plurality of partial pressure chambers 9.1, 9.2, which preferably have the same partial pressure surfaces for a uniform support of the shoe 6. The total effect cross section of the partial pressure chambers 9.1, 9.2 corresponds again substantially the cross section of the cylinder chamber 11. Otherwise, the above statements apply accordingly ,

In all the embodiments described above, the shoe 6 may be made of metal or plastic. As metal preferred for the shoe 6 is steel, brass, gunmetal or bronze. Furthermore, the shoe may consist of an aluminum or magnesium alloy. Furthermore, it is preferred that the shoe for improving the emergency running properties consists of a cast material, in particular gray cast iron (GGL), spherulitic cast iron (GGG) or vermiculares cast iron (GGV).

As plastic for the shoe 6, in particular a fiber-reinforced plastic is used, wherein preferably aramid, glass fiber or carbon fiber reinforcements are used.

The shoe 6 may also carry in all described embodiments on its underside 33 a hard layer of a wear-resistant material.

The sealing member 8 may have in all the embodiments described above, a rim 38 as a sealing edge, which carries a cover layer of a wear-resistant material. Further, the sealing member 8 may include a housing 35 having a T-shaped configuration, the T-bar or support plate 52 is made of brass, gunmetal or bronze. Alternatively, the sealing member 8, a support plate of a cast material, in particular gray cast iron (GGL), spherulitic cast iron (GGG) or vermiculares cast iron (GGV) have.

The sealing member 8 may have a support plate 52 which has a high flexural rigidity, whereas the shoe 6 has a low flexural rigidity. The different flexural stiffness is adjustable, for example, by different thicknesses, as in the eighth embodiment according to Fig. 2h shows. Thereafter, the shoe 6 is kept thin and preferably has a thickness in the range between 5 and 30 mm, in particular 5 to 15 mm, at a thinnest point of a preferably concave-shaped shoe. In contrast, the support plate 52 is made thicker with a thickness preferably in the range between 10 and 60 mm.

The different bending stiffnesses between shoe 6 and carrier plate 52 can also be adjusted by different E-modules of the materials used.

According to a ninth in Fig. 2i illustrated embodiment, the sealing member 8 at its end facing away from the shoe 6 a collar 53, which is submersible when lowering the seal member 8 in a groove 54 of the cylinder chamber 11.

The shoe 6 is hinged to the support 3 via spaced single point fasteners 55, 56. Preferably, two single point fasteners 55, 56 are provided which engage the shoe 6 in the quarter points of the shoe length, as in FIG Fig. 4 shown.

The Fig. 5 to 8 show examples of the arrangement of a plurality of hydraulic elements with their respective pressure chambers 9 in the machine direction L. In each case two juxtaposed in the direction L hydraulic elements are provided, each having a pressure chamber 9. In the cross machine direction Q, the hydraulic elements are arranged with their pressure chambers in series. It can be provided that the two respectively arranged in series pressure chambers 9 only on the inlet and outlet side with edge chambers 12, 13 are provided, as in Fig. 6 and Fig. 8 is shown.

Alternatively, the two respectively arranged in series pressure chambers 9 on the inlet and outlet side and between each two pressure chambers with edge chambers 12, 13 are provided, as in Fig. 5 and Fig. 7 is shown.

Furthermore, it can be provided that the at least two edge chambers 12, 13 form a pressure curve in the extended nip 5 via selectable pressure forces and / or form changeable on the outlet side.

Claims (16)

1. Apparatus for forming at least one extended nip between a mating roll (1) and a shoe roll (2) for treating a product web, wherein the shoe roll (2) has a stationary support (3) and a flexible roll shell (4) which is rotatable about the support (3) and is supported in the region of the extended nip (5) on a shoe (6) which is guided on the support (3), forms a pressing section and has an effective shoe width, and the shoe (6) can be pressed against the mating roll (1) via at least one hydraulic element (7), wherein the at least one hydraulic element (7) is configured as a cylinder/piston unit on the support (3), the shoe (6) being mounted in a floating manner on said cylinder/piston unit, characterized in that the hydraulic element (7) has as piston a sealing member (8) having a hydrostatic pressure chamber (9) which is open towards the shoe (6), has an encircling edge, is optionally composed of a plurality of partial pressure chambers, can be subjected, via at least one duct (10), to the working force of the pressure medium in a cylinder chamber (11) as supporting force, has an overall effective cross section corresponding substantially to the effective cross section of the cylinder chamber (11) and has a supporting force in a region offset on the outlet side towards a centre (Ms) of the effective shoe width (SBw), and at least two further edge chambers (12, 13) are provided, which further edge chambers (12, 13) are spaced apart from the pressure chamber (9), are open towards the shoe (6), have an encircling edge and can be supplied, as hydrostatic bearings, with a pressure medium via throttling points (14, 15).
2. Apparatus according to Claim 1, characterized in that a plurality of hydraulic elements (7) are arranged in a manner distributed along a shoe length and are controllable in a manner combined into zones.
3. Apparatus according to Claim 2, characterized in that at least hydraulic elements (17, 18) that are arranged at the ends are individually controllable.
4. Apparatus according to Claim 1, characterized in that a plurality of hydraulic elements (7) are arranged in a manner distributed along a shoe length and are each individually controllable.
5. Apparatus according to one of Claims 1 to 4, characterized in that at least in each case one edge chamber (12, 13) is arranged on the inlet side and outlet side of each pressure chamber.
6. Apparatus according to one of Claims 1 to 4, characterized in that at least in each case one edge chamber (12, 13) is arranged on the inlet side and outlet side of a zone of at least two pressure chambers (9).
7. Apparatus according to one of Claims 1 to 6, characterized in that the at least two edge chambers (12, 13) are arranged symmetrically to the centre of the sealing member.
8. Apparatus according to one of Claims 1 to 6, characterized in that the at least two edge chambers (12, 13) are arranged symmetrically to the centre of an overall shoe width.
9. Apparatus according to one of Claims 1 to 6, characterized in that the at least two edge chambers (12, 13) are arranged symmetrically to the centre (MD) of the sealing member (8) and offset on the outlet side in the machine running direction (L) with respect to the centre of the overall shoe width.
10. Apparatus according to one of Claims 1 to 6, characterized in that at least in each case one edge chamber (12, 13) is arranged on the inlet side and the outlet side, wherein the edge chamber (13) on the inlet side in the machine running direction (L) is arranged at a greater spacing from the pressure chamber (9) than the edge chamber (12) arranged on the outlet side.
11. Apparatus according to one of Claims 1 to 10, characterized in that the edge chambers (12, 13) are configured in a round manner and in each case four mutually-spaced apart edge chambers (12, 12', 13, 13') surround one or more pressure chambers (9).
12. Apparatus according to one of Claims 1 to 11, characterized in that the cylinder of a hydraulic element (7) is configured as a blind hole (32) in the support (3), said blind hole (32) having a cylinder chamber (11).
13. Apparatus according to Claim 12, characterized in that the effective cross section of the pressure chamber (9) is the same as the effective cross section of the blind hole (32).
14. Apparatus according to one of Claims 1 to 13, characterized in that the at least one duct (10) that leads from a cylinder chamber (11) to the pressure chamber (9) is configured without a throttle.
15. Apparatus according to one of Claims 1 to 14, characterized in that the sealing member (8) is spring-preloaded against the shoe (6) via a spring element (43).
16. Apparatus according to one of Claims 1 to 15, characterized in that the sealing member (8) can be preloaded against the shoe (6) via an inner supporting piston (44).

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