Shoe press for paper and related methods

Abstract

A shoe press (1) comprises a flexible cylindrical sleeve (5) cooperating with a counter roller (205) and defining a pressure nip (8) therewith. A shoe (7) is arranged inside the cylindrical sleeve and supported by a support beam (3) by means of a rod (21). The rod (21) is hinged to the support beam (3) about a first hinge axis (25), while the shoe is hinged to the rod about a second hinge axis (23) parallel to the first hinge axis (25).

Description

Technical Field

[0001] The present invention relates to improvements to papermaking machinery. The embodiments disclosed herein are particularly directed to improvements to a shoe press used to reduce the amount of water in a cellulose ply used to produce paper. Background Art

[0002] In the wet-laid papermaking process, a thin layer of an aqueous suspension of cellulose fibers is formed on a forming wire. The layer of aqueous suspension is distributed from a headbox arranged in the transverse direction of the forming wire and initially contains a very low weight percentage of fibers (usually about 2-10%). The water content gradually decreases along the feeding path, thereby forming a cellulose layer with a gradually increasing content of solid fractions (i.e., cellulose fibers).

[0003] Typically, the first part of the water removal occurs by drainage through the forming wire, optionally with the aid of suction rolls or boxes. When the percentage of dry material is high enough so that the cellulose ply formed by the gradual removal of water from the suspension of cellulose fibers has suitable mechanical strength, the cellulose ply is passed through a drying press and finally through a heating member, such as the rolls of a dryer or a Yankee cylinder.

[0004] In recent years, in order to obtain a more delicate treatment of paper (which maintains the thickness of the paper as much as possible during the step of removing water by pressing), shoe presses have been developed. Examples of shoe presses and their uses are disclosed in US10697120, US8986506, US7150110, US6517672, US7291249, US6158333, WO2007 / 123457.

[0005] Typically, a shoe press comprises a flexible cylindrical sleeve with two rigid heads supported by support bearings for rotation about an axis of rotation transverse to the feeding path of the felt to which the cellulose ply is adhered. Inside the flexible cylindrical sleeve, a fixed beam extends parallel to the axis of rotation of the flexible cylindrical sleeve and orthogonal to the path of the cellulose ply to be dried. On the support beam is mounted a shoe of suitable shape, which co-acts with the inner surface of the flexible cylindrical sleeve and is pressed radially outwards against the inner surface of the flexible cylindrical sleeve by a plurality of actuators. The flexible cylindrical sleeve co-acts with a rigid counter roller or cylinder having an axis of rotation parallel to the axis of rotation of the sleeve. The sleeve and the counter roller or cylinder form an extended pressure nip through which the annular flexible element, typically a felt, passes with the cellulose ply adhered thereto. The shoe presses the sleeve against the opposing roller or cylinder, exerting pressure on the felt and cellulose ply, whereby water is expelled from the cellulose ply.

[0006] Between the inner surface of the sleeve and the surface of the shoe cooperating therewith, a fluid (usually oil) is distributed to form a gap that reduces the friction between the sleeve and the shoe.

[0007] The counter roller or cylinder can be formed by a counterpressure roller or by a Yankee cylinder.

[0008] Historically, shoe presses have been used to generate relatively high linear loads (approximately 1500 kN / m) in the pressure nip for the production of paper and board. These high thrusts are usually generated by hydraulic actuators using high pressure oil supplied by a specific hydraulic circuit with an associated pump.

[0009] In recent years, shoe presses have been introduced in the field of tissue production. In these applications, the shoe presses usually act directly on the Yankee cylinder. The linear loads applied in the pressure nip are substantially low (approximately 90-120 kN / m). These loads can be generated by pneumatic actuators instead of hydraulic actuators, which significantly simplifies the structure of the press and its drive.

[0010] An important feature of a shoe press in the tissue sector is the possibility of applying a load distribution in the pressure nip in the transverse direction (i.e. orthogonal to the feeding direction of the cellulose ply), in particular in the lateral region (i.e. near the head of the Yankee cylinder). This makes it possible to compensate for any deformation of the Yankee cylinder by means of the pressure distribution.

[0011] Another important feature is that the resultant force in the pressure nip can be adjusted in the machine direction (ie in the feed direction of the flexible cylindrical sleeve and the felt) in order to modify the specific pressure distribution along the nip. This feature is applied in the water removal process.

[0012] WO2004 / 079090 discloses a shoe press in which the shoe is rigidly fixed to a rod hinged to a support beam inside a flexible cylindrical sleeve co-acting with counter-pressing rollers. The geometry of this shoe press is not efficient as it allows only one angular operating position.

[0013] WO2019 / 138349 discloses a shoe press, which comprises a relative roller, against which an annular flexible element is pressed by a shoe, which defines a pressure nip together with the annular flexible element and the relative roller. The shoe is supported inside the annular flexible element by a beam and has a radial movement towards the relative roller. In addition, in order to maintain the annular flexible element in a tensioned state, a support element is also arranged inside the annular flexible element, which is positioned at a certain distance from the shoe and the pressure nip. The internal support element can be moved radially and angularly by a dual actuator system to modify its position relative to the shoe. The boot (that is, the member that presses against the relative member) has only radial movement relative to the annular flexible element.

[0014] It would therefore be beneficial to provide a shoe press that allows for greater efficiency and that wholly or partially overcomes the problems of prior art shoe presses. Summary of the invention

[0015] According to one aspect, a shoe press is provided, the shoe press comprising an annular flexible element movable along a closed path. The annular flexible element may be a substantially cylindrical sleeve or housing, but this is not required. In addition, the press comprises a support beam housed inside the annular flexible element. The shoe is supported by the support beam and extends parallel to the support beam inside the annular flexible element. An opposing member is disposed outside the annular flexible element, the opposing member together with the annular flexible element defining a pressure nip for passing a cellulose layer. In addition, the press comprises a plurality of actuators aligned along the support beam and adapted to generate a thrust of the shoe against the opposing member, thereby acting on the inner surface of the annular flexible element. The shoe is supported by a rod, the rod being hinged to the support beam about a first hinge axis extending parallel to the support beam. The actuator is arranged to act on the rod to rotate the rod about the first hinge axis. Characteristically, the shoe is hinged to the rod about a second hinge axis.

[0016] The opposing member may be a rotating counter-roll or counter-cylinder, in particular having a peripheral speed substantially the same as the peripheral speed of the cellulose ply pressed against it by the shoe press. As will be explained below, in the embodiments disclosed herein, the opposing member may be a Yankee cylinder, in particular a Yankee cylinder for producing tissue paper.

[0017] With respect to the shoe presses of the prior art, in particular with respect to the shoe presses described in WO 2004 / 079070, important technical effects are achieved with the shoe presses according to the invention.

[0018] In fact, in the operating principle of the shoe press, two parameters defining the operating position of the shoe are related, namely:

[0019] - the distance between the operating surface of the shoe and the surface of the counter member (eg counter cylinder or counter roller);

[0020] - The angular orientation of the shoe, ie its inclination.

[0021] These two parameters must be kinematically independent of each other, since each depends in a different way on the compressibility of the means (polyurethane sleeve forming said annular flexible element, cellulose ply, felt for feeding said cellulose ply) interposed between the boot and the relative member and on the hydraulic backpressure generated by the dynamic conditions of the lubricating oil or other bearing fluid contained in the materials (felt, cellulose ply) and in the gap between the boot and the inner surface of the annular flexible element. The latter is determined by the velocity and the physical properties of the oil. In other words, at each given distance of the boot from the relative member, the boot must be free to adopt any angular position, in order to adapt itself to the dynamic conditions. This condition is necessary to ensure the function of the hydrodynamic lubrication of the boot and, from a process point of view, it is very important to obtain the desired pressure distribution in the machine direction in order to correctly remove the water.

[0022] The arrangement shown in prior art patent application WO2004 / 079090 limits the angular positioning of the shoe to its distance from the opposing cylinder by means of a rod to which the shoe is rigidly fixed and is therefore ineffective and unsuitable for the purpose. The shoe press of the present invention solves this problem.

[0023] Conveniently, the second hinge axis can be located on the side of the lever opposite to the side facing the support beam, i.e. on the side facing the pressure nip. Furthermore, advantageously, the second hinge axis can be positioned in an intermediate position of the lever between the point of connection of the first hinge axis and an actuator, the actuator controlling the movement of the lever about the first hinge axis.

[0024] The opposing member may be an annular flexible element or, preferably, a rigid roller. The terms "rigid" and "flexible" mean relative and refer to the normal operating conditions of the shoe press. Thus, the opposing member is a member that is more rigid (i.e., less susceptible to deformation under load) relative to the annular flexible element. While the annular flexible element deforms during operation to assume the shape defined by the active surface of the shoe (usually concave), the opposing member does not normally undergo any significant deformation under the load conditions normally applied in a shoe press.

[0025] In the embodiments disclosed herein, the opposing member may be constituted by a Yankee cylinder, or another roll of a dryer of a paper machine.

[0026] Typically, the opposing members have a peripheral motion at a speed that is substantially the same as the feed speed of the cellulosic ply through the pressure nip.

[0027] According to another aspect, a method for pressing a cellulose ply is disclosed herein, wherein the cellulose ply is guided through a pressure nip formed between an annular flexible element movable around a support beam and a counter member located outside the annular flexible element by means of a shoe extending parallel to the support beam and supported on a rod. The rod is hinged to the support beam around a first hinge axis and is pressed against the inner surface of the annular flexible element by a plurality of actuators aligned along the support beam. The shoe is hinged to the rod around a second hinge axis.

[0028] Further advantageous features and embodiments of the method and the shoe press according to the invention are described below and defined in the appended claims, which form an integral part of the present description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be better understood through the following description and the accompanying drawings, which illustrate non-limiting exemplary embodiments of the present invention. More specifically, in the accompanying drawings:

[0030] Figure 1 shows a schematic side view of an endless paper machine in which a Yankee cylinder cooperates with a shoe press;

[0031] Figure 2 A schematic side view of the shoe press is shown;

[0032] Figure 3 , Figure 4 and Figure 5 An embodiment of the shoe press is shown; and

[0033] Figure 6 The improved embodiment is shown according to Figure 3 Partial view of VI-VI. DETAILED DESCRIPTION

[0034] Figure 1 A schematic side view of a tissue paper making machine 2 is shown. The paper making machine 2 is known per se and may adopt different configurations known to those skilled in the art. Therefore, its features will not be described in detail.

[0035] It is sufficient to mention that the paper machine 2 comprises a headbox 201 which forms a layer of cellulosic pulp on a forming wire or other water-permeable endless flexible member, which comprises a wire and / or a felt and is generally indicated by 203. The cellulosic pulp is gradually drained by known means to reduce its water content until it reaches a Yankee cylinder 205 which cooperates with the shoe press 1. The felt 203 or other endless flexible element passes between the shoe press 1 and the Yankee cylinder 205, and downstream of the shoe press, the cellulosic fiber ply is separated from the felt 203 and adheres to the Yankee cylinder for drying. A doctor blade 207 separates the dried ply (indicated by V) from the Yankee cylinder 205.

[0036] exist Figure 2 A schematic diagram of a section according to a plane orthogonal to the axis of the shoe press 1 is shown in FIG. In this figure, the shoe press 1 cooperates with a Yankee cylinder 205. However, it should be understood that the shoe press 1 can be arranged, for example, upstream of a Yankee cylinder 205 or used in a paper machine 2 that does not have a Yankee cylinder 205 but is provided with a series of drying rollers or other drying devices. Figure 2 The member indicated by 205 in the subsequent figures may be, in addition to a Yankee cylinder, any other anvil member, preferably in the form of a rotating roller or cylinder.

[0037] As in Figure 2 , the shoe press 1 comprises a support beam 3 extending in a transverse direction relative to the feed direction F of the cellulose ply V on which the shoe press 1 has to act. The support beam 3 is attached at its ends to a bearing structure not shown. A flexible cylindrical sleeve 5 with a rotation axis A extends around the support beam 3, the rotation axis A being substantially parallel to the longitudinal extension of the support beam 3 and therefore parallel to the transverse machine direction (orthogonal to the feed direction F of the cellulose ply V through the shoe press 1).

[0038] A shoe 7 having an active surface 7A in contact with the inner surface of the flexible cylindrical sleeve 5 is arranged between the support beam 3 and the flexible cylindrical sleeve 5. The active surface 7A has a profile shaped to form a pressure nip 8 of suitable shape and extension between the outer surface of the flexible cylindrical sleeve 5 and an opposing surface formed, for example, by the cylindrical surface of the Yankee cylinder 205. In a manner known per se, a lubrication gap is formed between the active surface 7A of the shoe 7 and the inner surface of the flexible cylindrical sleeve 5, into which lubrication gap a bearing fluid, for example oil, is supplied.

[0039] In some embodiments, the lubrication may be of the hydrostatic type, as is typical in prior art shoe presses. In this case, the bearing fluid is distributed under pressure through a pipe whose end opens into a cavity located on the active surface 7A of the shoe 7 of the press 1. The pressure of the bearing fluid is provided by a supply circuit.

[0040] Characteristically, in the embodiments described herein, the bearing fluid can be supplied from outside the gap and the pressure can be generated by a hydrodynamic effect, that is, by the speed difference between the inner (movable) surface of the flexible cylindrical sleeve and the (fixed) active surface 7A of the shoe 7. In this case, the lubrication obtained in the gap between the shoe 7 and the flexible cylindrical sleeve is a lubrication of the hydrodynamic type.

[0041] It is also possible to combine the two types of lubrication.

[0042] The opposing surface formed by the Yankee cylinder 205 or other opposing member rotates in the opposite direction relative to the rotation direction of the cylindrical sleeve 5. The peripheral speeds of the flexible cylindrical sleeve 5 and the opposing surface are approximately the same in absolute value. The shape of the active surface 7A of the shoe 7 and the shape of the opposing surface of the Yankee cylinder 205 are substantially complementary to each other so as to form an extended pressure nip 8 having an approximately constant height (a dimension orthogonal to the opposing surface) along the path of the cellulosic ply through the nip 8.

[0043] The Yankee cylinder 205 or other opposing roller rotates at a feed speed that is substantially the same as the speed of one of the endless flexible members 203 that passes through the pressure nip 8 formed between the Yankee cylinder 205 and the portion of the flexible cylindrical sleeve 5 that is pressed against the Yankee cylinder 205 by the shoe 7.

[0044] Characteristically, the shoe 7 is connected to a rod 21 having a first end 21A articulated to the support beam 3 by a hinge defining a first hinge axis 25 parallel to the support beam 3 and to the axis of rotation A. The rod 21 is thus articulated to the support beam 3 so as to pivot about the first hinge axis 25 .

[0045] The shoe 7 is hinged to the rod 21 by a hinge forming a second hinge axis 23. In practice, the shoe 7 is thus hinged to the rod 21 so as to rotate about the second hinge axis 23. The hinge axis 23 is approximately parallel to the rotation axis A of the flexible cylindrical sleeve 5 and to the first hinge axis 25. At the opposite end 21B, the rod 21 is connected to a thrust actuator 27 which generates a thrust of the shoe 7 against the opposing surface 9. The thrust actuator 27 is Figure 2 The invention is shown schematically in the drawings and may take various forms, some of which are described below with reference to the remaining figures.

[0046] In practice, the shoe press 1 comprises a plurality of actuators 27 aligned along the longitudinal extension of the shoe 7 and of the support beam 3 , ie parallel to the axis of rotation A of the flexible cylindrical sleeve 5 .

[0047] Figure 3 Two series of thrust actuators 27A and 27B are schematically shown, wherein each series of thrust actuators comprises a plurality of actuators aligned in the direction of the longitudinal extension of the support beam 3 and the shoe 7 .

[0048] Each actuator 27 may be a hydraulic actuator. In a preferred embodiment, in particular in the case where the shoe press 1 is associated with a Yankee cylinder 205, the actuators 27 are pneumatic actuators, which have a simpler construction and do not require a hydraulic drive circuit.

[0049] The arrangement of the two series of actuators 27A, 27B ensures that a sufficiently high linear pressure is generated in the pressure nip 8 .

[0050] The actuators 27A, 27B may include actuators utilizing synthetic materials such as synthetic rubber. This type of actuator may include an air spring, a torpress, or an equivalent actuator.

[0051] In other embodiments, the actuator may include a piston-cylinder actuator. Figure 4 An embodiment using multi-stage pneumatic piston-cylinder actuators is shown, wherein each actuator comprises a cylinder divided into two chambers 28A, 28B in which two pistons 29A, 29B connected to a single rod 31 move. The double actuator thus obtained, also indicated with 27, generates a thrust which is the sum of the thrusts generated on the two pistons 29A, 29B by the pressurized fluid in the two chambers 28A, 28B. In this way, high thrusts are obtained with a compact and simple arrangement.

[0052] Using the rod 21 and a shoe 7 made of a sufficiently flexible material, by using a plurality of actuators 27 controlled independently of one another or in groups, a linear pressure distribution of the desired form can be generated along the longitudinal extension of the pressure nip 8, i.e. in the transverse direction relative to the feed direction F (machine direction) of the annular flexible element 203 and the cellulose layer V adhered thereto.

[0053] This makes it possible to counteract any local or global deformation of the opposing surface formed by the Yankee 205 or by another opposing cylindrical member. This is particularly advantageous in the case where the opposing surface is formed by the outer surface of the Yankee 205, which may deform in use due to its large size and its internal temperature and pressure. For example, and in particular, the Yankee 205 may expand radially more in the center than in the vicinity of the head, forming a bulge. Autonomous control of the single actuator 27 makes it possible to counteract this differential expansion, thereby avoiding greater pressure in points where the expansion is higher relative to points where the expansion is lower.

[0054] Although it is generally preferred to make each actuator 27 or each pair of actuators in a plurality of series of actuators 27A, 27B aligned along the axis of rotation of the flexible cylindrical sleeve 5 independent of each other, this is not strictly necessary. For example, the actuators may be divided into a plurality of groups aligned along the longitudinal direction of the support beam 3 and the shoe 7 (i.e. parallel to the axis of rotation A of the flexible cylindrical sleeve 5). The actuators of each group may be controlled together, and the individual groups may be controlled independently of each other.

[0055] Figure 6 A modified embodiment is schematically shown, in which the rod 21 is divided into a plurality of segments or parts 21C which are aligned along the longitudinal extension of the support beam 3 and thus parallel to the hinge axes 23 , 25 . Figure 6 Based on Figure 3 The configuration of the rod in section 21C can be used in any embodiment and can also be used in Figure 2 , Figure 4 and Figure 5 middle.

[0056] Each sector 21C of the rod 21 is stressed by at least one respective thrust actuator 27 or by a pair of thrust actuators 27A, 27B. The division of the rod 21 into sectors 21C allows greater operating flexibility and greater independence of the individual actuators in applying to the shoe 7 a load that can vary along the extension of the pressure nip 8.

[0057] In an improved embodiment, one or more auxiliary actuators 35 may be associated with the shoe 7, such as Figure 5 In a practical embodiment, a series of auxiliary actuators 35 may be provided which are aligned along the linear extension of the shoe 7. Also in this case, the auxiliary actuators 35 may preferably be pneumatic actuators.

[0058] The auxiliary actuators 35 may be independent of each other, or divided into groups independent of each other.

[0059] Each auxiliary actuator 35 is interposed between the shoe 7 and the rod 21. If the rod 21 is divided into parts or sections 21C, such as Figure 6 As shown in , at least one auxiliary actuator 35 may be provided for each section 21C of the rod 21. The auxiliary actuator 35 allows the shoe 7 to rotate about the second hinge axis 23. In this way, the direction of the resultant force of the pressure applied by the shoe 7 on the opposing surface formed by the Yankee cylinder 205 or other opposing members can be modified. If the auxiliary actuators 35 are independent of each other individually or in groups, the resultant force of the pressure can be applied in a variable direction along the longitudinal extension of the shoe 7.

[0060] Although the embodiments described above and shown in the drawings are provided with a cylindrical flexible sleeve 5, it is also possible to use an annular flexible element which is not cylindrical in shape, for example an annular flexible element formed by a belt driven around a series of rollers and forming a non-cylindrical closed path.

[0061] In any case, the annular flexible element defines a closed path around the support beam 3, and the pressure shoe 7 is mounted on the support beam 3 around the axes 23, 25 by a double hinge, and the pressure shoe presses against the inner surface of the annular flexible element, thereby forming an extended pressure roller gap between the outer surface of the annular flexible element and the opposite surface outside the annular flexible element.

[0062] In some embodiments, the shoe 7 can be made of a composite material. For example, the shoe 7 can be made of a material having a matrix consisting of a polymer resin, the material containing reinforcing fibers, such as glass fibers or preferably carbon fibers. In some embodiments, the polymer material can be an epoxy resin.

[0063] In order to obtain a more efficient operation, the shoe 7 may have anisotropic properties, i.e. different physical properties in different spatial directions. For example, the shoe 7 may have different elastic moduli in the machine direction (i.e. the feeding direction of the ply V through the pressure nip 8) and in the cross-machine direction (i.e. the direction parallel to the support beam 3 and the longitudinal extension of the shoe 7).

[0064] In some embodiments, the shoe 7 may have a higher elastic modulus in the feed direction F of the cellulose ply V through the pressure nip 8 than in the cross-machine direction (ie, parallel to the support beam 3 and transverse to the feed direction F of the cellulose ply V).

[0065] Furthermore, in the above description, specific reference has been made to a configuration in which the shoe press is mainly used to reduce the moisture content in the cellulose ply and, for this purpose, the shoe press cooperates with a felt or other flexible conveying member on which the cellulose ply is supported, which passes through the pressure nip. However, the features of the novel shoe press disclosed herein can also be used in a calender in which the cellulose ply can pass through the pressure nip without the support of an annular member. In some embodiments, vice versa, a double flexible conveying member can also be used, for example comprising two felts between which the cellulose material ply V is held.

Claims

1. A shoe press (1), comprising: - an annular flexible element (5) capable of moving along a closed path; - a support beam (3) housed inside the annular flexible element (5); - a shoe (7) supported by the support beam (3) and extending inside the annular flexible element (5) parallel to the support beam (3); - a counter-member (205) which is outside the annular flexible element (5) and which defines, together with the annular flexible element (5), a pressure nip (8) for the passage of the cellulose ply (V), the pressure nip being formed between the counter-member (205) and the shoe (7); - a plurality of actuators (27; 27A, 27B) aligned along the support beam (3) and adapted to generate a thrust of the shoe (7) against the counter member at the pressure nip (8); wherein the shoe (7) is supported by a rod (21) which is hinged to the support beam (3) about a first hinge axis (25) extending parallel to the support beam (3), and wherein the actuator (27; 27A, 27B) is arranged to act on the rod (21) to rotate the rod about the first hinge axis (25); Characterized in that the shoe (7) is hinged to the rod (21) about a second hinge axis (23).

2. The shoe press (1) according to claim 1, wherein: The rod (21) comprises a first end (21A) hinged to the first hinge axis (25), and a second end (21B).

3. The shoe press (1) according to claim 2, wherein: The actuator (27; 27A, 27B) acts in the vicinity of the second end (21B) of the rod (21).

4. The shoe press (1) according to claim 2, wherein: The second hinge axis (23) is located along the rod (21) between the first end (21A) and the second end (21B).

5. The shoe press (1) according to claim 3, wherein: The second hinge axis (23) is located along the rod (21) between the first end (21A) and the second end (21B).

6. Shoe press (1) according to any one of the preceding claims, wherein The actuator (27; 27A, 27B) is a pneumatic actuator.

7. The shoe press (1) according to claim 6, wherein: The pneumatic actuator is a pneumatic piston-cylinder actuator or a pneumatic spring actuator.

8. Shoe press (1) according to any one of claims 1-5, comprising two series of actuators (27A; 27B), each series of actuators comprising a plurality of actuators aligned in the direction of the support beam (3) and the shoe (7).

9. The shoe press (1) according to any one of claims 1 to 5, wherein: The rod is divided into a plurality of sections (21C) positioned side by side along the longitudinal extension of the support beam (3) and the shoe (7).

10. The shoe press (1) according to claim 9, wherein: At least one actuator (27; 27A, 27B) acts on each section (21C) of the rod (21).

11. The shoe press (1) according to claim 9, wherein: At least two actuators (27A, 27B) act on each section of the rod.

12. The shoe press (1) according to claim 9, wherein: The actuators (27; 27A, 27B) of each segment (21C) or groups of segments of the rod (21) are controlled independently of each other.

13. The shoe press (1) according to any one of claims 1 to 5, wherein: At least one of the actuators (27; 27A, 27B) comprises a serially connected multi-stage piston-cylinder actuator.

14. Shoe press (1) according to any one of claims 1-5, comprising at least one auxiliary actuator (35) arranged to act between the rod (21) and the shoe (7).

15. Shoe press (1) according to any one of claims 1-5, comprising a series of auxiliary actuators (35) arranged to act between the rod (21) and the shoe (7).

16. The shoe press according to claim 15, wherein: The auxiliary actuators (35) are controlled independently of each other or in independent groups.

17. The shoe press according to claim 14, wherein: Each auxiliary actuator (35) is a pneumatic actuator.

18. The shoe press (1) according to any one of claims 1 to 5, wherein: The shoe (7) is made of an anisotropic material having an elastic modulus in the feeding direction (F) of the cellulose layer through the pressure nip (8) that is greater than the elastic modulus in the direction transverse to the feeding direction (F) of the cellulose layer (V) through the pressure nip (8).

19. The shoe press (1) according to any one of claims 1 to 5, wherein: The boot (7) is made of a composite material.

20. The shoe press according to claim 19, wherein: The boot (7) is made of a fiber-filled polymer material.

21. A method for pressing a cellulose layer (V), wherein: The cellulose layer is guided through a pressure nip (8), which is formed between an annular flexible element (5) movable around a support beam (3) and a relative member (205) located outside the annular flexible element (5) by means of a shoe (7), the shoe (7) extending parallel to the support beam (3) and supported on a rod (21), the rod (21) being hinged to the support beam (3) around a first hinge axis (25) and being pressed against the inner surface of the annular flexible element (5) at the pressure nip (8) by means of a plurality of actuators aligned along the support beam (3); wherein the shoe is hinged to the rod (21) around a second hinge axis (23).

22. The method according to claim 21, wherein: The shoe (7) is pressed at least by an auxiliary actuator (35) acting between the shoe (7) and the rod (21).

23. The method according to claim 21 or 22, wherein: The cavity between the active surface (7A) of the shoe (7) and the inner surface of the annular flexible element (5) is subjected to hydrodynamic lubrication, or hydrostatic lubrication, or a combination of hydrodynamic lubrication and hydrostatic lubrication.

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