Belt for pulp or paper machine with sensors for pressure detection during operation and press using the same belt.

Description

1 / 15 “BELT FOR PULP OR PAPER MACHINE WITH SENSORS FOR PRESSURE DETECTION DURING OPERATION AND PRESS USING THE SAME” Related Request

[001] The present application claims priority and benefit of U.S. Provisional Patent Application No. 63 / 501,893, filed May 12, 2023, the description of which is incorporated herein by reference. Field of the Invention

[002] The present invention relates generally to clamping presses and, more particularly, to shoe presses. Background of the Invention

[003] In the conventional Fourdrinier papermaking process, an aqueous pulp, or suspension, of cellulosic fibers (known as paper stock) is fed into the upper part of the top passage of an endless belt of braided wire and / or synthetic material that moves between two or more rollers. The belt, often called the forming fabric, provides a papermaking surface on the upper surface of its top passage, which acts as a filter to separate the cellulosic fibers of the paper stock from the aqueous medium, thus forming a wet paper web. The aqueous medium drains through mesh openings in the forming fabric, known as drain holes, by gravity or vacuum, located on the lower surface of the top passage (i.e., the machine side) of the fabric.

[004] After leaving the forming section, the paper web is transferred to a press section of the paper machine, where it passes through the holes of one or more presses (often roller presses) covered with another fabric, typically called press felt. The pressure from the presses removes additional moisture from the sheet; moisture removal is often enhanced by Petition 870250091345, dated 07 / 10 / 2025, p. 7 / 44 2 / 15 presence of a felt blanket layer from the press. The paper is then transferred to a drying section for further moisture removal. After drying, the paper is ready for secondary processing and packaging.

[005] Over the last 35 or 40 years, a shoe press has been developed for the press section of the papermaking machine. A shoe press includes a roller or similar structure that fits into a shoe of an opposing roller or press frame; the surface of the shoe is somewhat concave and approximates in curvature the convex profile of the corresponding roller. This arrangement can increase the nip width in the direction of paper travel, thus allowing greater amounts of water to be removed.

[006] Endless belts or blankets have traditionally been used in shoe press operations. The belt covers and comes into contact with the press shoe; in turn, the press felt covers the shoe press belt, and the paper blanket covers the press felt. The shoe press belt and press felt run along the nip and, in doing so, carry the paper blanket across the nip. The press felt runs along a set of rollers arranged around the shoe. In older versions, shoe press belts were also driven by sets of drive rollers arranged around the shoe. In some more recent configurations, however, the shoe press belt is attached or otherwise fixed to the edges of circular head plates located at each end of the shoe, so that rotation of the head plates causes the shoe press belt to rotate and run along the nip.

[007] Considering the performance requirements, a shoe press belt must be flexible enough to pass around the drive rollers or head plates and through the shoe, and durable enough to withstand repeated application of Petition 870250091345, dated 07 / 10 / 2025, page 8 / 44 3 / 15 pressure inside the nip. Due to these performance parameters, most endless belts are formed entirely or predominantly of a polymeric material (often polyurethane). Many shoe press belts also include reinforcing fibers or a reinforcing fabric between or embedded in polymeric layers. Furthermore, shoe press belts can be configured to encourage water passage from the paper web. To this end, some shoe press belts have grooves or blind holes on the surface adjacent to the press felt, which serve to drain water from the paper that exits the felt.

[008] As the paper web is conveyed through the nip, it can be very important to understand the pressure profile experienced by the paper web. Variations in nip pressure can impact the amount of water drained from the sheet, which can affect the final moisture content of the sheet, thickness, and other properties. Excessive nip pressure can cause crushing or tearing of the sheet. Obviously, in a shoe press, the pressure typically varies at different locations on the nip, both along and across the direction of paper travel, and can also vary over time. As a result, it would be desirable to have a reliable technique and apparatus for determining the pressure distribution and nip area in a shoe press. Summary

[009] As a first aspect, embodiments of the invention are directed to a pressure-sensing belt for a shoe press or similar. The belt comprises: a substantially cylindrical polymeric belt with a longitudinal axis, a radially inner surface and a radially outer surface; a plurality of transverse-machine (CD) reinforcing fibers extending parallel to the longitudinal axis along the length Petition 870250091345, dated 07 / 10 / 2025, p. 9 / 44 4 / 15 belt section between the inner and outer surfaces; a plurality of transverse-machine (MD) reinforcing fibers extending circumferentially with respect to the longitudinal axis between the inner and outer surfaces; and a plurality of piezoelectric fibers extending within the belt, each of the piezoelectric fibers having a sensing portion and a signal-carrying portion.

[0010] As a second aspect, embodiments of the invention are directed to a shoe press employing a belt as described above. Brief Description of the Figures

[0011] Figure 1 is a front view of a shoe press of the present invention.

[0012] Figure 2 is a front cutaway view of the lower roller and belt of the shoe press of Figure 1.

[0013] Figure 3 is a perspective view of the shoe press belt of Figure 1 with the outer polymer layer removed to reveal the CMD fibers.

[0014] Figure 4 is a partial enlarged view of the end of the shoe press belt of Figure 1, illustrating the reinforcing and piezoelectric fibers.

[0015] Figure 5 is an enlarged partial perspective view of the shoe press belt of Figure 1 with the outer polymer subsequently removed to show the reinforcing CMD fibers and piezoelectric fibers.

[0016] Figure 6 is a schematic front view of an exemplary piezoelectric fiber used in the shoe press belt of Figure 1.

[0017] Figure 7A is a schematic front view of another exemplary piezoelectric fiber that can be used with the belt of Petition 870250091345, dated 07 / 10 / 2025, page 10 / 44 5 / 15 shoe press in Figure 1.

[0018] Figure 7B is a schematic front view of the piezoelectric fiber of Figure 7A shown with the piezoelectric core cleaved.

[0019] Figure 8 is a partial perspective view of the shoe press belt of Figure 1 with the sensing portions of the piezoelectric fibers shown at different lengths to allow sensing of different axial locations on the shoe press belt.

[0020] Figure 9 is a front cutaway view of the shoe press shown in Figure 2 with the processing unit illustrated schematically. Detailed Description of the Invention

[0021] The present invention is described in more detail below, with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention can, however, be implemented in many different forms and should not be interpreted as limited to the embodiments presented here; rather, these embodiments are provided so that this description is complete and comprehensive, and fully conveys the scope of the invention to those skilled in the art.

[0022] Equal numbers refer to elements that are equal throughout. In figures, the thickness of certain lines, layers, components, elements, or features may be exaggerated for clarity. Dashed lines illustrate optional features or operations unless otherwise specified.

[0023] The terminology used herein is intended to describe specific embodiments only and is not intended to limit the invention. As used herein, the singular forms a, an, and the should also include plural forms unless the context clearly indicates otherwise. It should further be understood that the terms comprise and / or comprising, when used herein Petition 870250091345, dated 07 / 10 / 2025, p. 11 / 44 6 / 15 specification, specify the presence of declared features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. As used herein, the term and / or includes any and all combinations of one or more of the associated listed items. As used herein, phrases such as between X and Y and between approximately X and Y should be interpreted as including X and Y. As used herein, phrases such as between approximately X and Y mean between approximately X and approximately Y. As used herein, phrases such as from approximately X to Y mean from approximately X to approximately Y.

[0024] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning commonly understood by someone with common knowledge of the art to which this invention pertains. It should further be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with their meaning in the context of the specification and the relevant art and should not be interpreted in an idealized or overly formal sense, unless expressly so defined herein. Well-known functions or constructions may not be described in detail for reasons of brevity and / or clarity.

[0025] It should be understood that when an element is referred to as being on, fixed to, connected to, coupled to, in contact with, etc., another element, it may be directly on, fixed to, connected to, coupled to, or in contact with the other element, or intervening elements may also be present. In contrast, when an element is referred to as being, for example, directly on, directly fixed to, directly connected to, di Petition 870250091345, dated 07 / 10 / 2025, p. 12 / 44 7 / 15 directly coupled to or in direct contact with another element, there are no intervening elements present. It will also be understood by those skilled in the art that references to a structure or feature disposed adjacent to another feature may have portions that overlap or lie beneath the adjacent feature.

[0026] With reference now to Figures 1 and 2, a shoe press, broadly designated as 20, is illustrated therein. The shoe press 20 includes a lower roller 22 and an upper roller 24 coupled together, which define between them a nip 25 through which a sheet or roll, such as a paper blanket 37, can move. Each of the lower and upper rollers 22 and 24 defines a respective axis A1, A2; the axes A1 and A2 are essentially parallel to each other and substantially perpendicular to the MD direction of movement of the blanket 37. As can be seen in Figure 1, the pressing felts 35 and 36 are positioned between the lower and upper rollers 22 and 24; The pressing felts 35 and 36 are driven around respective sets of drive rollers 35a and 36a by the lower and upper rollers 22 and 24. The blanket 37 is transported by and between the pressing felts 35 and 36.

[0027] Referring once again to Figures 1 and 2, the lower roller 22 includes a beam 26 that extends parallel to axis A1. At each end, the beam 26 includes a circular shaft 28 that engages with and is supported by a bracket 30. A shoe 32 with a concave pressure surface 33 extends upward from the beam 26. The shoe 32 is mounted on the beam 26 so that it can be tilted upward in a controlled manner; the tilting of the shoe 32 can be achieved with, for example, a hydraulic system (not shown). A circular head plate 34 is rotatably mounted on each shaft 28, spaced from the end of the shoe 26. Bearings 37 allow the head plates 34 to rotate on the shaft 28. Petition 870250091345, dated 07 / 10 / 2025, p. 13 / 44 8 / 15

[0028] A substantially cylindrical shoe press belt or sleeve 40 is mounted around the perimeter of each headplate 34, so that its longitudinal axis is substantially parallel to axis A1. The shoe press belt 40 is fixed to the headplates 34 (by means of clamps or similar) so that, as the headplates 34 rotate around the axes 28, they also cause the shoe press belt 40 to rotate. Typically, the shoe press belt 40 is between 101 and 213 cm in diameter and between 304 and 1,227 cm in length.

[0029] As shown in Figure 1, the lower and upper rollers 22 and 24 are positioned relative to each other so that the upper roller 24 causes the shoe press belt 40 to deviate from a cylindrical configuration and conform to the pressing surface configuration 33 of the shoe 32. The pressing surface 33 of the shoe 32 is shaped to be substantially complementary to the convex profile of the upper roller 24, resulting in a contact area 25 with significant width and extended in the MD direction (this dimension is typically between about 3 and 12 inches). Both the shoe 32 and the upper roller 24 can be adjusted to control the magnitude and distribution of pressure on the contact area 25; in particular, the shoe 32 can be pivotable about an axis parallel to axis A1, allowing the pressure to be adjusted along the direction of displacement of the MD blanket.As the belt of the shoe press 40 rotates with the head plates 34, parts of it are deflected by the contact surface 24a of the upper roller 24 to come into contact with the contact surface 33 of the shoe 32.

[0030] Those skilled in the art will recognize that the present invention may be suitable for shoe presses of other configurations. For example, the lower roller 22 may include a fixed shaft. Petition 870250091345, dated 07 / 10 / 2025, page 14 / 44 9 / 15 and a hydraulic shoe (such as that available from the Voith Group, Heidenheim, Germany, under the NipcoFlex brand), or it may be replaced by an isolated shoe, where the shoe press belt is guided through the shoe by a set of drive rollers. The upper roller 24 may be hydraulically supported (as is the case with the NipcoFlex press mentioned above), may include an adjustable convex shoe (such as that available from the Voith Group, under the NipcoFlex brand) or may not have adjustability. Other exemplary shoe presses include those available from Valmet (SymBelt), Bellmer (TURBOPRESS) and Beloit (ENP-C). Furthermore, the lower and upper members may be oriented so that the concave pressing surface of the shoe is displayed by the upper member of the shoe press and the convex pressing surface is displayed by the lower member of the shoe press.These and other suitable shoe press configurations are described and illustrated in Joint Textbook Committee of the Paper Industry, Pulp and Paper Manufacture, Vol. 7, 267-70 (Third Edition, 1991). Alternative configurations should include a shoe with an adjustable concave pressing surface and a coupling structure (such as a roller or opposing convex shoe) that forms a contact space through which a shoe press belt passes.

[0031] Figures 3-5 illustrate the shoe press belt 40 in greater detail. Most of the shoe press belt 40 is composed of a polymeric material, such as polyurethane or rubber, which serves as the matrix 42. Normally, the material that makes up the entire matrix 42 will be the same, but not necessarily; the matrix 42 may comprise layers of different materials. An example of a material for use in the matrix 42 is a polyurethane material with a Shore A hardness value between about 55 and 100.

[0032] As can be seen in Figure 4, the press belt of Petition 870250091345, dated 07 / 10 / 2025, p. 15 / 44 10 / 15 shoe 40 also includes reinforcing yarns or fibers. One set of fibers 44 is oriented in the MD direction (i.e., they extend circumferentially within the matrix 42 of the shoe press belt 40, often as a single continuous helically wound fiber). Another set of fibers 46, which is located radially outward from the MD fibers 44, is oriented in the CMD direction (i.e., they extend axially within the matrix of the shoe press belt 40). Fibers 44, 46 may be any fibers recognizably suitable for inclusion in the reinforcement of a shoe press belt 40. Fibers 44, 46 may be formed in any size and from any material suitable for use in a shoe press belt; Exemplary fibers include those formed from polyester, nylon, or ultra-high molecular weight polyethylene (UHMWPE), which may have a denier between approximately 1,000 and 1,200 and may be twisted into 2, 3, or 6 layers.Fibers 44 and 46 can be included at any density / frequency, but are typically spaced so that there are 8 to 12 fibers per inch.

[0033] Fibers 44 and 46 are included in the shoe press belt 40 to provide reinforcement in the machine directions and transverse to the machine. As used herein, fibers 44 and 46 are intended to cover both fabrics (such as those illustrated in U.S. Patent No. 5,196,092 to Stigberg) and reinforcing structures such as those shown, which include the constructions described and illustrated in U.S. Patent No. 5,525,194 to Jermo, descriptions of which are incorporated herein in full.

[0034] The radially outer surface of the die 42 of the shoe press belt 40 may include grooves or similar features that can improve the dewatering capacity of the shoe press belt 40. Such grooves are typically MD grooves, although they may also include holes and similar features. Exemplary groove patterns are Petition 870250091345, dated 07 / 10 / 2025, page 16 / 44 11 / 15 illustrated and described in U.S. Patent No. 8,083,899 to Kawamata, the description of which is incorporated herein in full by reference.

[0035] As shown in Figure 5, the shoe press belt 40 also includes a plurality of piezoelectric fibers 100 that serve as pressure sensors. The piezoelectric fibers 100 are configured to include a sensing portion 102 that generates a signal under pressure and a signal carrier portion 104 (see Figure 6) that carries the signal from the sensing portion 102 to a processing unit 56 (described below). As an example, the sensing portion 102 may be formed of a piezoelectric material, such as piezoelectric polymers, piezoelectric ceramics, and piezoelectric compounds. The signal carrier portion 104 may be any type of communication cable through which the information generated by the sensing portion 102 may pass; exemplary materials for the signal carrier portion may be magnetic wire or other conductive wire (insulated or not).In some cases, the piezoelectric fiber 100 may also include a non-conductive portion 106 (see Figure 6) that extends beyond the piezoelectric portion (for example, a polyester fiber).

[0036] In some cases, piezoelectric fiber 100 may be a layer or component of a multilayer or multicomponent fiber; for example, piezoelectric fiber 100 may be the core of a multilayer fiber that also includes an outer protective sheath made of a different material (see Figure 7A).

[0037] Piezoelectric fibers 100 are shown here as fibers CD, although in some embodiments piezoelectric fibers may also be included in the machine direction. Typically, the piezoelectric fibers 100 are positioned substantially equidistant from each other around the circumference of the shoe press belt 40; For example, the piezoelectric fibers 100 may be separated Petition 870250091345, dated 07 / 10 / 2025, page 17 / 44 12 / 15 radas by approximately 15 degrees, so that the 40 shoe press belt includes 24 100 piezoelectric fibers.

[0038] In the illustrated embodiment, and as shown in Figure 9, each of the piezoelectric fibers 100 is configured so that the sensing portion 102 is located at a different axial location on the shoe press belt 40. (For example, a first of the sensing portions 102 may be located adjacent to one end of the shoe press belt 100, a second of the sensing portions 102 may be located 30 cm from that end of the shoe press belt 100, a third of the sensing portions may be located 60 cm from that end of the shoe press belt 100, and so on along the entire length of the shoe press belt 40. This type of arrangement allows pressure measurement at different axial locations on the shoe press belt 40, which can provide the operator with a complete pressure profile along the shoe press belt 40.This pressure profile can allow the operator to identify and correct problems at the correct location on the paper machine. The sensing portions 102 are typically positioned substantially equidistant from each other along the belt of the shoe press 40, but other configurations, such as those in which the sensing portions 102 are more concentrated in one or more areas of particular interest, can also be used.

[0039] In one embodiment, each of the piezoelectric fibers 100 is co-located or combined with one of the CD 46 fibers; for example, each piezoelectric fiber 100 can be helically wrapped around a CD 46 fiber, or the piezoelectric fiber 100 can be routed adjacent to a CD 46 fiber. This embodiment may have the advantage of being able to utilize the existing CD 46 fiber as a “main structure” supporting the piezoelectric fiber 100, so that the Petition 870250091345, dated 07 / 10 / 2025, p. 18 / 44 13 / 15 piezoelectric fiber 100 does not need to extend the entire length of the shoe press belt 40. In such an embodiment, it may be desirable to fix the end of the piezoelectric fiber to the CD fiber by means of an adhesive or similar.

[0040] In another embodiment, each of the piezoelectric fibers 100 replaces one of the CD fibers 46 in the matrix 42, so that the total number of CD fibers (i.e., CD fibers 46 plus piezoelectric fibers 100) remains unchanged. In this embodiment, the piezoelectric fiber 100 extends the entire length of the shoe press belt 100 (see Figures 6 and 7A). In this configuration, each of the piezoelectric fibers 100 can be modified to provide a sensing portion at a different axial location along the length of the shoe press belt 40. This can be achieved by replacing the portion of the piezoelectric fiber 100 opposite the signal carrier portion 104 with a non-conductive material (shown at 106 in Figure 6). In another version, the piezoelectric core of a multilayer fiber can be cleaved at a desired location, so that a signal is sent only to the portion of the piezoelectric fiber 100' upstream of the cleave point (Figure 7B). Other variations may also be possible.

[0041] Each of the piezoelectric fibers 100 is operationally connected to a processing unit (schematically represented by 56 in Figure 9). The processing unit 56 can be mounted on one of the head plates 34, above one end of the shoe press belt 40, or in another convenient location. As an example, the processing unit 56 can be a wireless voltage reader mounted just above one end of the shoe press belt 40 (see Figure 9), so that it can read the voltages present in the signal carrier elements as each passes under the voltage reader. Alternatively, the piezoelectric fibers can be connected to the unit of Petition 870250091345, dated 07 / 10 / 2025, page 19 / 44 14 / 15 processing 56.

[0042] The processing unit 56 may also include a device or sensor that can identify which piezoelectric fiber 100 is producing the signal being read. This can be achieved in several ways. One example is mounting an RFID tag or transmitter associated with each piezoelectric fiber 100 so that, as the shoe press belt 40 rotates during operation, an RFID reader detects the RFID tag and can correlate the received signal with the correct piezoelectric fiber 100. As another example, the piezoelectric fibers 100 may be sufficiently separated from each other circumferentially so that only one fiber is present in the nip at a time, so that identifying which fiber 100 is sending a signal can be simplified.

[0043] The processing unit 56 includes a signal transmitter 58 that communicates with a signal receiver 62 mounted remotely on the shoe press 20. The signal receiver 62 is connected by wiring to a personal computer 64 or other data processing device (such as the distribution control system of a paper mill) that can process signals from the transmitter 58 into useful and easily understandable information. It is preferable that a wireless communication mode, such as RF signaling (e.g., Bluetooth® protocol), be used to transmit data from the processing unit 56 to the receiver 62.

[0044] The shoe press belt 40 may be constructed by any known method for constructing shoe press belts, such as casting, molding, extrusion, or the like. One method of construction is discussed in U.S. Patent No. 7,014,733 to Gustafson et al., the description of which is hereby incorporated by reference in full.

[0045] A shoe press belt 40 incorporating piezoelectric fibers 100, as described above, may provide information in Petition 870250091345, dated 07 / 10 / 2025, page 20 / 44 15 / 15 real-time information on operational parameters at the nip, such as pressure magnitude and distribution, nip width, deformation, and tension. This information can allow an operator to adjust the shoe press 20 as desired for the papermaking operation in question. For example, it may be desirable to adjust the shoe 32 so that the pressure inside the nip 25 remains at a certain magnitude. As another example, it may be desirable to adjust the shoe 32 so that the peak pressure experienced at the nip 25 is located at the “downstream” end of the nip 25, rather than in the center, as this may improve the quality of the paper formed on it.

[0046] It is also considered that a belt of the present invention may be suitable for other uses. These may include, for example, other locations in a papermaking machine (e.g., calendering belts and Clupak blankets), belts for pulp machines and belts for textile machines.

[0047] It is also considered that pressure-sensitive materials, in addition to piezoelectric fibers, can be used.

[0048] The foregoing is illustrative of the present invention and should not be construed as limiting it. Although examples of embodiments of this invention have been described, those skilled in the art will readily understand that many modifications are possible in the exemplary embodiments without departing materially from the new teachings and advantages of this invention. Consequently, all such modifications should be included within the scope of this invention as defined in the claims. The invention is defined by the following claims, with equivalents of the claims to be included therein. Petition 870250091345, dated 07 / 10 / 2025, page 21 / 44

Claims

1 / 3 CLAIMS 1. Pressure-sensing belt, characterized in that it comprises: a substantially cylindrical polymeric belt with a longitudinal axis, a radially inner surface and a radially outer surface; a plurality of machine-direction (CD) reinforcing fibers extending parallel to the longitudinal axis along the length of the belt, between the inner and outer surfaces; a plurality of machine-direction (MD) reinforcing fibers extending circumferentially with respect to the longitudinal axis between the inner and outer surfaces; and a plurality of piezoelectric fibers extending within the belt, each of the piezoelectric fibers having a sensing portion and a signal-carrying portion.

2. Belt, according to claim 1, characterized in that the polymeric belt comprises polyurethane.

3. Belt according to claim 1, characterized in that the polyurethane has a Shore A hardness value between about 55 and 100.

4. Belt, according to any one of claims 1 to 3, characterized in that each of the sensing portions of the piezoelectric fibers is positioned at a different axial location.

5. Belt, according to any one of claims 1 to 3, characterized in that each of the piezoelectric fibers includes a non-conductive portion and extends the entire length of the belt.

6. Belt, according to claim 5, characterized in that each of the piezoelectric fibers is positioned to replace one of the reinforcing CD fibers.

7. Belt, according to any one of claims 1 to 3, characterized in that each of the piezoelectric fibers is colocalized with one of the reinforcing CD fibers.

8. Belt according to claim 7, characterized in that each of the piezoelectric fibers extends for less than the length of the belt.

9. Belt, according to claim 8, characterized in that each of the piezoelectric fibers is helically wound around a corresponding CD reinforcing fiber.

10. Belt, according to any one of claims 1 to 3, characterized in that the sensing portions comprise a piezoelectric polymer and the conductive portions comprise a magnetic wire.

11. Belt, according to any one of claims 1 to 3, characterized in that said outer surface includes a plurality of recesses for water ventilation.

12. Belt, according to any one of claims 1 to 3, characterized in that said piezoelectric fibers are spaced substantially equidistant from each other along a circumference of the belt.

13. Belt, according to any one of claims 1 to 3, characterized in that it further comprises at least one piezoelectric fiber routed in the MD direction.

14. Shoe press, characterized in that it comprises: a first member with a convex pressing surface; a second member comprising a shoe with a concave pressing surface substantially complementary to said convex pressing surface, said second member further comprising a pair of substantially circular head plates mounted in rotational mode at axially opposite ends; a belt, as defined in claim 1, mounted on the head plates; and a processing unit in communication with piezoelectric fibers that processes the signals generated by the sensing portions.

15. Shoe press, according to claim 14, characterized in that the first member comprises an elongated roller.

16. Shoe press, according to claim 14, characterized in that it further comprises an endless press felt positioned to be carried between said belt and said pressing surface of the second member.

17. Shoe press, according to claim 14, characterized in that the processing unit is mounted above one end of the belt in axial alignment with the shoe.

18. Shoe press, according to claim 17, characterized in that said processing unit comprises a signal transmitter, and in that said shoe press further comprises a signal receiver and a display device operatively associated with said signal transmitter.

19. Shoe press, according to claim 17, characterized in that an identifier is associated with each of the piezoelectric fibers, the identifier being configured to provide a signal to the processing unit indicating the retraction of the associated piezoelectric fiber. Petition 870250091345, dated 07 / 10 / 2025, p. 24 / 44

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