Sealing strip wear monitoring system and assembly thereof

Abstract

A seal strip for a suction roller of a paper machine having a wear monitoring system includes: a seal strip having an upper surface; and a wear monitoring system. A wear monitoring system includes a sensor including a first conductive layer, a second conductive layer, and a resistive layer, the first and second conductive layers mounted on the resistive layer, the second conductive layer being separate from the first conductive layer. The wear monitoring system further includes a signal processor electrically connected to the first conductive layer and the second conductive layer and configured to process a signal related to a resistance between the first conductive layer and the second conductive layer. The sensor is at least partially embedded in the sealing strip.

Description

[0001] Related Applications This application claims priority and benefits to U.S. Provisional Patent Application No. 63 / 584,626, filed September 22, 2023, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0002] This invention relates generally to papermaking, and more specifically to suction rollers and equipment within a papermaking machine. Background Technology

[0003] Papermaking inherently requires the removal of water at many points during the production process. Typically, pulp (a mixture of water and wood and other fibers) is carried on top of felt (in the form of wide strips), which acts as a carrier for the wet pulp before actual paper is formed. The felt is used to carry the pulp in the wet section of the paper machine until sufficient water is removed from the pulp to allow the paper to be processed without the additional support provided by the felt.

[0004] Quite commonly on the wet end of a paper machine, initial water removal is accomplished using a suction roll (whether a couch roll, pickup roll, or press suction roll) in the press section, used in conjunction with a non-perforated standard press roll (or, in a tissue paper machine, opposite a Yankee dryer), which is aligned with the suction roll. The felt pulp carrier is pressed between these two rolls.

[0005] The main components of the suction roller 10 include a hollow shell 12 made of stainless steel, bronze or other metals. Figure 1 The hollow shell has tens of thousands of holes radially drilled around the circumference of the roll in a prescribed pattern. The size of these holes is measured (ranging from less than 1 / 8" to nearly 1 / 4") and designed for the specific paper material being processed. These holes form the "drainage outlets" for removing water. These outlets typically occupy approximately 20% to 45% of the effective roll surface area. The suction roll shell is driven by a drive system that rotates the shell around a stationary core called the suction box.

[0006] Suction box 20 ( Figure 2 The suction box 20 can be considered as a conventional long rectangular box without a top cover and with ports at the ends, bottom, or sides. The ends of the box (especially the drive ends) typically have guide bearings, the inner raceways of which are guide bushings or bearings having a sliding fit with journals on the suction box, and the outer raceways pressing against the rotating housing. The suction box 20 is connected to a suction source (e.g., a vacuum pump). An exemplary suction box and housing are shown in Huttunen’s U.S. Patent No. 6,358,370, the disclosure of which is incorporated herein by reference in its entirety.

[0007] To utilize the holes in the shell, these ports must be used to create a vacuum zone 30 on the inside of the suction roll shell in the area directly below the pulp being processed. This is achieved by the suction box 20 using a grooved retainer 32, which holds the seal along the long axis of the suction box on both sides. Figure 2 The grooved retainer 32 is shown, and Figure 3 and Figure 4 Two types of seals 34, 34' (hereinafter referred to as "seals") in the form of strips are shown. In addition to these long seals, there are two shorter seals (referred to as end seals) at the short ends (referred to as the drive end and the actuation end), which allow for some axial adjustment as needed to accommodate various sheet widths.

[0008] The sealing strips 34 and 34' are typically made of rubberized polymerized graphite and remain in near-contact with the inner surface of the housing 12 during operation (see [link]). Figure 3 and Figure 4 A constant vacuum is drawn between the sealing strips 34 and 34'. This allows a vacuum zone 30 to be created below the sheet 40 as it passes through the roller 10. The sealing strips 34 and 34' are biased upward toward the suction roller housing 12 by loading tubes 42, which are sealing hoses extending along the entire length of the sealing strips 34 and 34'. The pressure in the loading tubes 42 causes them to expand (much like air in a balloon) and lifts the sealing strips 34 and 34' toward the inner surface of the housing 12. This effect, along with the system vacuum from the suction box 20 and the aforementioned laminar flow of lubricating water, forms a seal between the edge of the sealing strip 34 and the inner side of the housing 12.

[0009] In practical applications, during normal operation of the suction roller, the sealing strips 34, 34' never directly contact the inner side of the suction roller housing 12. If the sealing strips 34, 34' contact the housing 12, they will wear off and quickly lose their sealing ability. To eliminate or significantly reduce this wear and provide a seal, water is applied along the length of the sealing strips 34, 34' using a lubricating spray formed by water flowing through the spray nozzle 24 (see...). Figure 2 The spray uses laminar water between the sealing surface and the inner surface of the housing 12 to keep the sealing strips 34, 34' lubricated.

[0010] The amount of water used for lubrication should be properly metered to apply an appropriate amount of lubrication to keep the seals 34, 34' lubricated, but not so much as to cause problems with the processed pulp or waste water. Additionally, the process water used in paper mills may contain chemicals and a large number of particles that can clog the humidification spray nozzles 24 during normal operation. Since these nozzles 24 are located inside the rotating housing 12, they are not visible to the paper machine operator.

[0011] Sealing strips are typically replaced periodically after a certain degree of wear. However, because the sealing strips inside the suction rolls are invisible to the operators of the papermaking equipment or anyone attempting to inspect them, many conditions inside the operating suction rolls, including the degree of wear on the sealing strips, are unknown. Therefore, a reliable method for detecting sealing strip wear may be desired to inform the papermaking equipment operators of the need for maintenance before a malfunction occurs. Summary of the Invention

[0012] As a first aspect, embodiments of the present invention relate to a sealing strip for a suction roll of a paper machine having a wear monitoring system, comprising: a sealing strip having an upper surface; and a wear monitoring system. The wear monitoring system includes a sensor comprising a first conductive layer, a second conductive layer, and a resistive layer, the first and second conductive layers being mounted on the resistive layer, and the second conductive layer being separate from the first conductive layer. The wear monitoring system further includes a signal processor electrically connected to the first and second conductive layers and configured to process a signal related to the resistance between the first and second conductive layers. The sensor is at least partially embedded in the sealing strip.

[0013] As a second aspect, embodiments of the present invention relate to a sealing strip for a suction roll of a paper machine with a wear monitoring system, comprising: a sealing strip having an upper surface; and a wear monitoring system. The wear monitoring system includes: a sensor comprising a first conductive layer, a second conductive layer, and a resistive layer, the first and second conductive layers being mounted on the resistive layer, the second conductive layer being separate from the first conductive layer; and a signal processor electrically connected to the first and second conductive layers and configured to process a signal related to the resistance between the first and second conductive layers. The first conductive layer has a free end adjacent to the upper surface of the sealing strip, the free end defining an edge of the first conductive layer that is substantially parallel to the upper surface. The sensor is wound into a coiled configuration and at least partially embedded in a hole within the sealing strip.

[0014] As a third aspect, embodiments of the present invention relate to a sealing strip for a suction roll of a paper machine with a wear monitoring system, comprising: a sealing strip having an upper surface; and a wear monitoring system. The wear monitoring system includes: a sensor comprising a first conductive layer, a second conductive layer, and a resistive layer, the first and second conductive layers being mounted on a common surface of the resistive layer, the second conductive layer being separate from the first conductive layer; and a signal processor electrically connected to the first and second conductive layers and configured to process a signal related to the resistance between the first and second conductive layers. The sensor is at least partially embedded in the sealing strip. The first conductive layer has a free end adjacent to the upper surface of the sealing strip, the free end defining an edge of the first conductive layer that is generally parallel to the upper surface. The width of the first conductive layer narrows as it extends from the edge away from the upper surface. Attached Figure Description

[0015] Figure 1 This is a typical end perspective view of a paper machine suction roller.

[0016] Figure 2 This is an enlarged end perspective view of the suction box area of ​​a typical suction roller.

[0017] Figure 3 This is an end view of the suction box area and sealing strip of a conventional suction roller.

[0018] Figure 4 This is an end view of the suction box area and sealing strip of another conventional suction roller.

[0019] Figure 5 This is a schematic perspective view of a wear sensor for a sealing strip according to an embodiment of the present invention.

[0020] Figure 6 This is a schematic perspective view of a wear sensor for a sealing strip according to an alternative embodiment of the present invention.

[0021] Figure 7 This is a schematic perspective view of a wear sensor for a sealing strip according to another embodiment of the present invention.

[0022] Figure 8 This is a schematic perspective view of a wear sensor for a sealing strip according to another embodiment of the present invention.

[0023] Figure 9 It is in a wound structure Figure 8 A schematic partial perspective view of the wear sensor.

[0024] Figure 10 It is embedded in the sealing strip Figure 8 A schematic front cross-sectional view of the wear sensor.

[0025] Figure 11 It is the sealing strip and the one embedded in the sealing strip. Figure 10 Top perspective view of the wear sensor. Detailed Implementation

[0026] The invention will now be described more fully below, with embodiments of the invention shown. However, the invention may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to make this disclosure exhaustive and complete, and to fully convey the scope of the invention to those skilled in the art. In the drawings, similar numerals always denote similar elements. The thickness and size of some components may be exaggerated for clarity.

[0027] Additionally, for ease of description, spatially related terms such as “below,” “under,” “lower,” “above,” and “upper” are used herein to describe the relationship between one element or feature as shown in the figures and another element(s). It should be understood that spatially related terms are intended to cover different orientations of the device in use or operation other than those shown in the figures. For example, if the device in the figures is flipped, an element described as “below” or “under” other elements or features would be oriented “above” other elements or features. Thus, the exemplary term “below” can encompass both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or otherwise), and the spatially related descriptive language used herein will be interpreted accordingly.

[0028] For the sake of brevity and / or clarity, well-known functions or structures may not be described in detail.

[0029] Referring now to the attached diagram, the wear sensor used in the sealing strip of the paper machine is generally marked 100, and... Figure 5 As shown in the diagram. As used herein, the term "paper machine" is intended to include any machine used to manufacture paper products, including conventional paper, cardboard / boardboard, toilet paper, and the like. Sensor 100 includes two conductive layers 102, 104 that are parallel to each other but spaced apart. A resistive layer 106 is sandwiched between the conductive layers 102, 104. Corresponding leads 108, 110 are connected to and extend from each of the conductive layers 102, 104. The leads 108, 110 are routed to a means (such as an ohmmeter 114) for detecting the resistance across the conductive layers 102, 104. The ohmmeter 114 is operatively connected to a processor 116 that receives the signal from the ohmmeter and processes the signal into an indication of the degree of wear experienced by the sealing strip.

[0030] The structure of sensor 100 causes the resistance measured between layers 102 to increase as the area of ​​layers 102, 104, 106 decreases (e.g., due to wear starting at the free end F of sensor 100). Therefore, if sensor 100 is embedded in a sealing strip, with the free end F parallel to and near the wear surface of the sealing strip, the wear experienced by the sealing strip during operation will also begin to wear away the free end F of sensor 100, thereby reducing the area of ​​layers 102, 104, 106 and increasing the measuring resistance of sensor 100. The increase in voltage is related to the degree of wear (e.g., depth) of the sealing strip.

[0031] Now see Figure 6 Another embodiment of the sensor is shown, generally designated 200. Similar to sensor 100, sensor 200 includes two conductive layers 202, 204 separated by a resistive layer 206 and leads 208, 210. However, as... Figure 6 As can be seen, conductive layers 202 and 204 are triangular in shape, as is the resistive layer 206 sandwiched between conductive layers 202 and 204. Leads 208 and 210 are attached to one of the "points" of the triangle defined by conductive layers 202 and 204. Leads 208 and 210 are attached to ohmmeters and processors, etc., for detecting the resistance between the conductive layers and providing an indication of wear.

[0032] Sensor 200 is embedded in a sealing strip, with its free end F2 (the side of the conductive layers 202, 204 and resistive layer 206 opposite to the attachment points of leads 208, 210) positioned parallel to and near the wear surface of the sealing strip. During operation, wear on the sealing strip wears away the free end F2. As this occurs, the area of ​​layers 202, 204, 206 decreases, thereby increasing the resistance between conductive layers 202, 204. However, since the end of sensor 200 adjacent to leads 208, 210 is much narrower than the free end F2, the rate of area reduction of layers 202, 204, 206 is increased compared to sensor 100. As a result, the resistance between conductive layers 202, 204 increases at a greater rate than that of sensor 100, given a similar wear depth. For the same wear depth, the increased resistance between sensors 100 and 200 makes sensor 200 more sensitive to small differences in wear depth.

[0033] Now see Figure 7Another wear sensor, generally designated 300, is shown. Sensor 300 includes conductive layers 302 and 304 mounted on resistive layer 306, but in this embodiment, conductive layers 302 and 304 are mounted on the same side of resistive layer 306 and separated by gap 314. Leads 308 and 310 are connected to layers 302 and 304, respectively. Leads 308 and 310 are connected to an ohmmeter / processor as described above, capable of detecting the resistance between conductive layers 302 and 304.

[0034] Similar to sensors 100 and 200, sensor 300 is mounted within the sealing strip such that its free end F3 is parallel to and positioned at or near the wear surface of the sealing strip. As the sealing strip wears, the free end F3 of sensor 300 begins to wear away, accompanied by an increase in resistance. The detection of this increase in resistance can then be correlated with the degree of wear of the sealing strip in the manner described above.

[0035] This sensor embodiment has advantages over sensors 100 and 200, namely, since the conductive layers 302 and 304 do not directly overlap each other, the risk of a "short circuit" between layers 302 and 304 is reduced or eliminated, whereas damage to the resistive layer of either sensor 100 or 200 can lead to a short circuit.

[0036] exist Figure 8 Another wear sensor, shown in the diagram and generally labeled 400, has a similar construction to sensor 300, namely, its conductive layers 402 and 404 are mounted on the same surface of resistive layer 406 rather than on opposite sides. However, conductive layer 402 is similar to conductive layer 202 of sensor 200, i.e., it is wider at its free end F4 than at the end connected to lead 408. As a result, as the free end F4 wears away, the resistance detected by the ohmmeter / processor attached to leads 408 and 410 as described above will be greater than the resistance detected for sensor 300 at the same depth, potentially providing a more accurate / more sensitive measurement of seal wear.

[0037] When installed within a sealing strip, any of the sensors 100, 200, 300, and 400 can maintain [their functionality]. Figures 5 to 8 The diagram shows a flat structure. However, a flat structure is not required. Figure 9 A construction is shown, in which Figure 8 The sensor 400 is wound into a spiral structure (i.e., the sensor 400 is wound around an axis parallel to the wear axis of the sensor 400), so that the free end F4 of the sensor 400 is arranged in a spiral at or near the wear surface of the sealing strip.

[0038] Figure 10 and Figure 11This illustrates how sensor 400 can be mounted in sealing strip 450. Hole 452 may be drilled or otherwise formed in sealing strip 450, and sensor 400 and its leads 408, 410 may be inserted into hole 452. In some embodiments, hole 452 may be partially or completely filled with a potting compound (e.g., epoxy resin). Leads 408, 410 extend from the lower end of the hole for attachment to an ohmmeter / processor as described above. Figure 10 It can also be seen that, in some embodiments, additional lines may extend between sensors mounted at other locations within the seal strip 450 to provide a complete wear profile across the length of the seal strip 450. Further discussion regarding the use of multiple wear sensors and how signals are extracted from them is set forth in U.S. Patent Application No. 18 / 347,943, filed July 6, 2023, the disclosure of which is incorporated herein by reference in its entirety.

[0039] Sensors 100, 200, 300, and 400 can be formed from any material deemed suitable for generating measurable resistance between conductive layers. In some embodiments, the conductive layers (e.g., layers 402 and 404) can be formed from copper foil. In other embodiments, the resistive layers can be formed from carbon films. Any one or both of these materials are flexible enough that they can be easily wound into sheets when contained in the form of a film. Figures 9 to 11 This allows the sensor to be mounted in a form that prevents it from breaking or cracking. In some embodiments, the conductive layer may be mounted on the resistive layer via a conductive adhesive (such as conductive acrylate, which may be pre-applied to a metal strip, such as copper strip) or conductive epoxy. The conductive adhesive may provide a conductive boundary layer that can introduce additional resistance.

[0040] Those skilled in the art will recognize that the sensors shown herein can take other forms. For example, although all the leads discussed herein are shown as bare wires, in many embodiments the wires may be insulated to prevent damage and / or short circuits. Additionally, conductive layers 202, 204, 402 are shown in a generally triangular shape; however, other shapes in which the conductive layer narrows from its free end to its mounting position on the lead may also be adopted. As an example, the long edge of conductive layer 402 (which in…) Figure 8 The path (shown as a straight line) can alternatively follow an arcuate path (e.g., a logarithmic path), which allows the sensor to be tuned for optimal accuracy. Other variations can also be conceived by those skilled in the art.

[0041] In addition, in some embodiments, wear sensors 100, 200, 300, 400 may be accompanied by a temperature sensor also embedded in the sealing strip.

[0042] The foregoing description illustrates the present invention and should not be construed as limiting it. Although exemplary embodiments of the invention have been described, those skilled in the art will readily understand that many modifications may be made to the exemplary embodiments without substantially departing from the novel teachings and advantages of the invention. Therefore, all such modifications are intended to be included within the scope of the invention as defined in the claims. The invention is defined by the appended claims, wherein equivalents of the claims are included therein.

Claims

1. A sealing strip for the suction roll of a paper machine with a wear monitoring system, comprising: A sealing strip with an upper surface; as well as Wear monitoring system, which includes: A sensor, comprising a first conductive layer, a second conductive layer, and a resistive layer, wherein the first conductive layer and the second conductive layer are mounted on the resistive layer, and the second conductive layer is separate from the first conductive layer; and A signal processor electrically connected to the first conductive layer and the second conductive layer, and configured to process signals related to the resistance between the first conductive layer and the second conductive layer; The sensor is at least partially embedded in the sealing strip.

2. The sealing strip and wear monitoring system according to claim 1, wherein, The resistive layer has a first surface and a second surface opposite to each other, wherein the first conductive layer and the second conductive layer are mounted to the first surface.

3. The sealing strip and wear monitoring system according to claim 1, wherein, The resistive layer has a first surface and a second surface opposite to each other, wherein the first conductive layer is mounted to the first surface and the second conductive layer is mounted to the second surface.

4. The sealing strip and wear monitoring system according to claim 1, wherein, The first conductive layer has a free end adjacent to the upper surface of the sealing strip, the free end defining an edge of the first conductive layer that is substantially parallel to the upper surface.

5. The sealing strip and wear monitoring system according to claim 4, wherein, The first conductive layer defines a generally triangular coverage area on the resistive layer, wherein the edge of the first conductive layer defines one side of the triangular coverage area.

6. The sealing strip and wear monitoring system according to claim 5, wherein, The second conductive layer defines a roughly triangular coverage area on the resistive layer.

7. The sealing strip and wear monitoring system according to claim 4, wherein, As the first conductive layer extends from the edge away from the upper surface, the width of the first conductive layer narrows.

8. The sealing strip and wear monitoring system according to claim 7, wherein, As the second conductive layer extends away from the upper surface, the width of the second conductive layer narrows.

9. The sealing strip and wear monitoring system according to any one of the preceding claims, wherein, The first conductive layer comprises a metal foil.

10. The sealing strip and wear monitoring system according to any one of the preceding claims, wherein, The resistive layer includes a carbon film.

11. The sealing strip and wear monitoring system according to any one of the preceding claims, wherein, The sensor is rolled up into a wound structure.

12. A sealing strip for the suction roll of a paper machine with a wear monitoring system, comprising: A sealing strip with an upper surface; as well as Wear monitoring system, which includes: A sensor, comprising a first conductive layer, a second conductive layer, and a resistive layer, wherein the first conductive layer and the second conductive layer are mounted on the resistive layer, and the second conductive layer is separate from the first conductive layer; and A signal processor electrically connected to the first conductive layer and the second conductive layer, and configured to process signals related to the resistance between the first conductive layer and the second conductive layer; The first conductive layer has a free end adjacent to the upper surface of the sealing strip, the free end defining an edge of the first conductive layer, the edge being substantially parallel to the upper surface; and The sensor is rolled up into a wound structure and is at least partially embedded in a hole in the sealing strip.

13. The sealing strip and wear monitoring system according to claim 12, wherein, The resistive layer has a first surface and a second surface opposite to each other, wherein the first conductive layer and the second conductive layer are mounted to the first surface.

14. The sealing strip and wear monitoring system according to claim 12, wherein, The resistive layer has a first surface and a second surface opposite to each other, wherein the first conductive layer is mounted to the first surface and the second conductive layer is mounted to the second surface.

15. The sealing strip and wear monitoring system according to claim 12, wherein, As the first conductive layer extends from the edge away from the upper surface, the width of the first conductive layer narrows.

16. The sealing strip and wear monitoring system according to any one of the preceding claims, wherein, The first conductive layer comprises a metal foil.

17. A sealing strip for the suction roll of a paper machine with a wear monitoring system, comprising: A sealing strip with an upper surface; as well as Wear monitoring system, which includes: A sensor, comprising a first conductive layer, a second conductive layer, and a resistive layer, wherein the first conductive layer and the second conductive layer are mounted on a common surface of the resistive layer, and the second conductive layer is separate from the first conductive layer; and A signal processor electrically connected to the first conductive layer and the second conductive layer, and configured to process signals related to the resistance between the first conductive layer and the second conductive layer; The sensor is at least partially embedded in the sealing strip; and The first conductive layer has a free end adjacent to the upper surface of the sealing strip, the free end defining an edge of the first conductive layer, the edge being substantially parallel to the upper surface; and As the first conductive layer extends from the edge away from the upper surface, the width of the first conductive layer narrows.

18. The sealing strip and wear monitoring system according to claim 17, wherein, The first conductive layer comprises a metal foil.

19. The sealing strip and wear monitoring system according to claim 17, wherein, As the first conductive layer extends from the edge away from the upper surface, the width of the first conductive layer narrows.

20. The sealing strip and wear monitoring system according to claim 17, wherein, The sensor is rolled up into a wound structure.

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