Monitoring system

Abstract

[Problem] To provide a monitoring system enabling prevention of occurrence of a failure by monitoring a status of a papermaking tool in operation. [Solution] The present invention relates to a monitoring system for monitoring the status of a papermaking tool used in wet parts WP, WP1, WP2. The wet parts WP, WP1, WP2 each includes, at least: the papermaking tool to be used in contact with wet paper X; a plurality of guide rolls for guiding the papermaking tool; a thermo camera 4 for capturing an image of the papermaking tool; and a control device 5 to which the thermo camera 4 is connected. The papermaking tool is a papermaking felt 2 or a papermaking wire 1. The control device 5 comprises: an imaging command transmission means 11 that transmits a command to cause the thermo camera 4 to capture an image; an acquisition means 12 that acquires thermography captured by the thermo camera 4; and a monitoring means 13 that monitors the state of the papermaking tool by the surface temperature of the papermaking tool in the thermography.

Description

surveillance system

[0001] The present invention relates to a monitoring system for monitoring the condition of papermaking tools used in the wet part of a papermaking machine.

[0002] A multi-cylinder paper machine for producing paperboard or paper has at least a wet part consisting of a wire part in which the stock is placed on a sheet-like papermaking wire (papermaking mesh) and excess water is allowed to fall off to form a wet paper, and a press part in which the wet paper is pressed with a press roll through a papermaking felt to transfer excess water in the wet paper to the papermaking felt, a dry part in which the wet paper that has passed through the press part is brought into contact with a dryer via a canvas to dry it into paper, and a reel part in which the paper is wound onto a spool. A household paper machine for producing household paper also has at least a wet part in which the stock is removed by a cylindrical papermaking wire (papermaking mesh) to form a wet paper and transported on a papermaking felt, a dry part in which the wet paper is brought into contact with a Yankee dryer via a canvas to dry it into paper, and a reel part in which the paper is wound onto a spool. Thus, a papermaking wire and a papermaking felt are used in the wet part of a paper machine.

[0003] Because papermaking machines produce paper continuously at high speeds, a drawback is that if a defect occurs in papermaking tools such as papermaking felts and papermaking wires that come into contact with the wet paper, the yield rate will drop significantly. Specifically, the main defects of papermaking felts are shedding and clogging due to long-term use. When a defect occurs in a papermaking felt, the degree to which the papermaking felt absorbs moisture from the wet paper varies, resulting in an uneven moisture profile across the width, which can lead to reduced paper quality, such as uneven thickness of the produced wet paper. Similarly, the main defect of a papermaking wire is clogging due to long-term use. When a defect occurs in a papermaking wire, the degree to which the papermaking wire passes (drops) moisture varies, resulting in an uneven moisture profile across the width, which can lead to reduced paper quality, such as abnormal formation of the wet paper. To prevent this, papermaking equipment is generally maintained on a regular basis, but this is by no means sufficient.

[0004] In response to this, systems for monitoring dryer rolls, canvas, or canvas rolls have been developed to prevent malfunctions during operation. For example, a monitoring system is known that includes a papermaking machine for producing paper, an application device for applying a chemical solution to a portion of the papermaking machine that comes into direct or indirect contact with the paper while the papermaking machine is operating, a control panel for setting application conditions for the application device, a surveillance camera for monitoring the monitored portion, and a control device connected to the surveillance camera via a network, where the monitored portion is the dryer roll, canvas, or canvas roll of the papermaking machine, and the control device includes a calculation unit that digitizes the state of the monitored portion by binarization using video captured by the surveillance camera, a display unit that displays detection data obtained by the calculation unit by quantifying the amount of change in the binarized value during operation from the binarized value in a steady state, and a memory unit that stores the detection data (see, for example, Patent Document 1).

[0005] Patent No. 6697132

[0006] However, it is difficult to apply the monitoring system described in Patent Document 1 to papermaking tools used in the wet part. That is, since the monitoring system uses images captured by a monitoring camera, it is not suitable for the wet part, which has a lot of moisture, and it is particularly difficult to recognize defects inside the papermaking felt, which has a lot of fibers, or defects in the papermaking wire, which has a fine mesh, from the image.

[0007] The present invention has been made in consideration of the above circumstances, and has as its object to provide a monitoring system that can prevent malfunctions from occurring by monitoring the state of papermaking tools during operation.

[0008] The present inventors have noticed that when a problem occurs in a papermaking tool (papermaking felt or papermaking wire) in the wet part, the water retention capacity of that part fluctuates. They also noticed that variations in water retention capacity of the papermaking felt or papermaking wire can be recognized as variations in its surface temperature. For example, Fig. 9(a) is a photograph of a papermaking felt in the field, Fig. 9(b) is a thermograph of the same, and Fig. 9(c) is a graph showing the water content in an arbitrary width direction. The part with high water content (water retention capacity) shown in Fig. 9(c) is difficult to recognize in the photograph of Fig. 9(a) but can be easily recognized in the thermograph of Fig. 9(b). The present inventors have found that the above-mentioned problems can be solved by providing a thermographic camera and a control device in the wet part and monitoring the papermaking tool (papermaking felt or papermaking wire) using the thermograph. This led to the completion of the present invention.

[0009] The present invention is a monitoring system for monitoring the condition of papermaking tools used in the wet part, wherein the wet part comprises at least papermaking tools used in contact with wet paper, a plurality of guide rolls for guiding the papermaking tools, a thermocamera for capturing images of the papermaking tools, and a control device to which the thermocamera is connected, wherein the papermaking tools are papermaking felt or papermaking wire, and the control device comprises an imaging command sending means for sending an imaging command to the thermocamera, an acquisition means for acquiring thermographs captured by the thermocamera, and a monitoring means for monitoring the condition of the papermaking tools based on the surface temperature of the papermaking tools in the thermograph.

[0010] In the monitoring system of the present invention, it is preferable that the monitoring means has a calculation means for calculating the temperature difference between the temperature of each pixel in the width direction at any position on the papermaking tool in operation and the average temperature of these temperatures, in the surface temperature of the papermaking tool in the thermography, and a judgment means for determining whether the temperature difference is within a predetermined threshold range, and that the condition of the papermaking tool is monitored by the judgment means.

[0011] In the monitoring system of the present invention, it is preferable that the wet part further has a spraying device for spraying chemical liquid onto the papermaking tools, and that the control device further has a spray command issuing means for issuing a command to the spraying device to spray the chemical liquid, and that when the determination means determines that the temperature difference at a predetermined position on the papermaking tools is outside the threshold range, the spray command issuing means issues a spray command to the spraying device, and the spraying device sprays the chemical liquid onto the predetermined position or increases the amount of chemical liquid sprayed onto the predetermined position.

[0012] In the monitoring system of the present invention, it is preferable that the monitoring means includes a calculation means for calculating the degree of temperature change over time for each pixel in the width direction at any position on the papermaking tool while it is in operation, based on the surface temperature of the papermaking tool in multiple thermographs acquired over time, and a determination means for determining whether the degree of temperature change is within a predetermined threshold range, and that the condition of the papermaking tool is monitored by the determination means.

[0013] In the monitoring system of the present invention, it is preferable that the wet part further has a spraying device for spraying chemical liquid onto the papermaking tools, and that the control device further has a spray command sending means for sending a command to the spraying device to spray the chemical liquid, and when the judgment means determines that the degree of temperature change at a predetermined position on the papermaking tools is outside the threshold range, the spray command sending means sends a spray command to the spraying device, and the spraying device sprays the chemical liquid onto the predetermined position or increases the amount of chemical liquid sprayed at the predetermined position.

[0014] In the monitoring system of the present invention, when the papermaking tool is a papermaking felt, the chemical solution preferably contains at least a surfactant and water, the surfactant being an anionic surfactant or a nonionic surfactant, and when the papermaking tool is a papermaking wire, the chemical solution preferably contains at least a water-soluble polymer and water, the water-soluble polymer being a cationic polymer or an amphoteric polymer.Furthermore, it is even more preferable that the chemical solution contains at least a surfactant, a water-soluble polymer, and water, the surfactant being an anionic surfactant or a nonionic surfactant, and the water-soluble polymer being a cationic polymer or an amphoteric polymer.

[0015] In the monitoring system of the present invention, it is preferable that the papermaking felt is a single-ply weave felt, a double-ply weave felt, a 2.5-ply weave felt, or a triple-ply weave felt, and the papermaking wire is a single-ply weave wire, a 1.5-ply weave wire, a double-ply weave wire, a 2.5-ply weave wire, a triple-ply weave wire, or a 3.5-ply weave wire.

[0016] In the monitoring system of the present invention, the wet part further has a cleaning device for performing a cleaning process in which cleaning water is sprayed onto the papermaking tools to clean them, and a suction box for performing a suction process in which the cleaning water is sucked in, and it is preferable that the cleaning device is arranged upstream of the suction box with respect to the transport of the papermaking tools, and the thermal camera is arranged upstream of the cleaning device or downstream of the suction box.

[0017] In the monitoring system of the present invention, the wet part has a thermal camera and a control device, so it is possible to obtain thermography that shows the surface temperature of papermaking tools during operation. In addition, in the monitoring system, the control device is equipped with monitoring means, so it is possible to monitor the condition of papermaking tools during operation using the surface temperatures of the papermaking tools shown in the thermography. In other words, the degree of a defect in the papermaking tools can be recognized from the surface temperature. This makes it possible to prevent a decrease in yield due to defects in papermaking tools during paper production.

[0018] If the papermaking tool is a papermaking felt, the temperature shown on the thermograph changes according to the water retention capacity of the papermaking felt, and the water retention capacity changes according to the degree of shedding and the degree of dirt on the papermaking felt. From this, it can be said that the temperature shown on the thermograph changes according to the degree of shedding and the degree of dirt on the papermaking felt. Similarly, if the papermaking tool is a papermaking wire, the temperature shown on the thermograph changes according to the water retention capacity of the papermaking wire, and the water retention capacity changes according to the degree of dirt on the papermaking wire. From this, it can be said that the temperature shown on the thermograph changes according to the degree of dirt on the papermaking wire.

[0019] Incidentally, when the temperature of the water supplied to the papermaking felt for dehydration of the wet paper is higher than the outside air temperature, such as when the paper stock is hot, the higher the surface temperature, the greater the water retention capacity. Conversely, when the temperature of the water supplied to the papermaking felt is lower than the outside air temperature, the lower the surface temperature, the greater the water retention capacity.

[0020] In the monitoring system of the present invention, the monitoring means includes a calculation means (first calculation means) that can recognize the degree of a defect at any position on the papermaking tool from the temperature difference. Also, the monitoring means includes a determination means (first determination means) that can accurately determine whether to continue using the papermaking tool in operation or replace it before the defect becomes severe.

[0021] In the monitoring system of the present invention, the monitoring means includes a calculation means (second calculation means), which allows the change in the degree of defect at any position on the papermaking tools to be recognized from the temperature change over time. Also, the monitoring means includes a determination means (second determination means), which allows the timing for replacing the papermaking tools to be predicted, making it possible to review the processing conditions of the wet part and prepare for the replacement of the papermaking tools in advance.

[0022] In the monitoring system of the present invention, the wet part has a spraying device and the control device is equipped with a spray command issuing means, so that measures can be taken such as quickly spraying chemical liquid at a specified position that is outside the range of the threshold value (first threshold value or second threshold value) or increasing the amount of chemical liquid sprayed at the specified position.

[0023] In the monitoring system of the present invention, when the papermaking tool is a papermaking felt, the chemical solution contains at least an anionic surfactant or a nonionic surfactant, which can effectively remove pitch that causes clogging of the papermaking felt. When the papermaking tool is a papermaking wire, the chemical solution contains at least a cationic polymer or an amphoteric polymer, which can effectively remove pitch that causes clogging of the papermaking wire. When the chemical solution contains an anionic surfactant or a nonionic surfactant and a cationic polymer or an amphoteric polymer, pitch can be effectively removed from any papermaking tool.

[0024] In the monitoring system of the present invention, when the papermaking felt is a single-ply, double-ply, 2.5-ply or triple-ply felt, and the papermaking wire is a single-ply, 1.5-ply, double-ply, 2.5-ply, triple-ply or triple-ply wire, if a malfunction occurs, the water retention capacity changes significantly, which has the advantage that the malfunction can be easily recognized.

[0025] In the monitoring system of the present invention, by placing the thermal camera upstream of the cleaning device or downstream of the suction box, the influence of the cleaning device spraying cleaning water onto the papermaking tools is minimized, allowing for more accurate monitoring of the papermaking tools.

[0026] FIG. 1 is a schematic side view showing a wet part in which a monitoring system according to this embodiment is used. FIG. 2 is a block diagram for explaining a control device in the monitoring system according to this embodiment. FIG. 3 is a flowchart showing the operation of the monitoring system according to this embodiment. FIG. 4 is a photograph showing an example of a thermograph of a papermaking felt taken by a thermal camera in the monitoring system according to this embodiment. FIG. 5 is a graph of a temperature profile displaying values ​​calculated by the first calculation means using the thermograph of the papermaking felt shown in FIG. 4. FIG. 6 is a table showing the results of thermography taken over time at the same position in the width direction L of the papermaking felt shown in FIG. 4. FIG. 7 is a schematic side view showing a wet part in which a monitoring system according to another embodiment is used. FIG. 8 is a schematic side view showing a wet part in which a monitoring system according to another embodiment is used. FIG. 9(a) is a photograph showing a papermaking felt at work. FIG. 9(b) is a thermograph of the photograph shown in FIG. 9(a). FIG. 9(c) is a graph showing the moisture content in an arbitrary width direction of the papermaking felt shown in FIG. 9(a).

[0027] Preferred embodiments of the present invention will be described in detail below, with reference to the drawings as necessary. In the drawings, identical elements are designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of the drawings are not limited to those shown.

[0028] The present invention relates to a monitoring system for monitoring the state of papermaking tools used in the wet part, such as papermaking felt and papermaking wire.

[0029] Fig. 1 is a schematic side view showing a wet part in which a monitoring system according to this embodiment is used. Fig. 1 shows the wet part of a multi-cylinder paper machine. Therefore, the wet part WP is composed of a wire part W and a press part P.

[0030] First, an example of monitoring a papermaking felt 2 (papermaking tool) in a press part P (wet part WP) will be described. As shown in Figure 1, the press part P has a papermaking felt 2 that is used in contact with a wet paper X and absorbs moisture contained in the wet paper X, a press roll 3 that presses the wet paper X in contact with the papermaking felt 2, a plurality of guide rolls that guide the wet paper X and the papermaking felt 2, a thermo camera 4 that takes images of the papermaking felt 2, a control device 5 to which the thermo camera 4 is connected, a cleaning device 6 that performs a cleaning process by spraying cleaning water onto the papermaking felt 2 to clean it, a suction box 7 that performs a suction process by sucking the cleaning water, and a spraying device 8 that sprays a chemical solution onto the papermaking felt 2.

[0031] In the press part P, the press rolls 3 have an upstream press roll 3a and a downstream press roll 3b arranged downstream of the upstream press roll 3a in the conveying direction of the wet paper X. Therefore, the wet paper X is dewatered by being pressed by the upstream press roll 3a and the downstream press roll 3b via the papermaking felt 2. Here, the upstream press roll 3a consists of a first top roll 3a1 and a first bottom roll 3a2 abutted against the first top roll 3a1, and the downstream press roll 3b consists of a second top roll 3b1 and a second bottom roll 3b2 abutted against the second top roll 3b1.

[0032] In the press part P, four papermaking felts 2 are installed: a first papermaking felt 2a, a second papermaking felt 2b, a third papermaking felt 2c, and a fourth papermaking felt 2d, all of which are endless. The first papermaking felt 2a passes between the first top roll 3a1 and the first bottom roll 3a2 and is guided upward by the other guide rolls. The second papermaking felt 2b passes between the first top roll 3a1 and the first bottom roll 3a2 and is guided downward by the other guide rolls. The third papermaking felt 2c passes between the second top roll 3b1 and the second bottom roll 3b2 and is guided upward by the other guide rolls. The fourth papermaking felt 2d passes between the second top roll 3b1 and the second bottom roll 3b2 and is guided downward by the other guide rolls.

[0033] Therefore, specifically, on the upstream press roll 3a, the wet paper X is pressed between the first top roll 3a1 and the first bottom roll 3a2, while being sandwiched between the first papermaking felt 2a and the second papermaking felt 2b, and on the downstream press roll 3b, the wet paper X is pressed between the second top roll 3b1 and the second bottom roll 3b2, while being sandwiched between the third papermaking felt 2c and the fourth papermaking felt 2d.

[0034] Here, single-weave felt, double-weave felt, 2.5-ply felt, triple-weave felt, laminated felt, non-woven felt, seamed felt, etc. can be used as the papermaking felt 2. Among these, it is preferable to use single-weave felt, double-weave felt, 2.5-ply felt, or triple-weave felt as the papermaking felt 2. These have the advantage that if a defect occurs, the water retention capacity changes significantly, making it easy to recognize the defect using the monitoring system of the present invention.

[0035] In the press part P, the thermo camera 4, the cleaning device 6, the suction box 7 and the spray device 8 are all installed so as to face the papermaking felt 2 (see the first papermaking felt 2a or the second papermaking felt 2b) that is not in contact with the wet paper X. It is also preferable that these are arranged so as to face the surface of the papermaking felt 2 that comes into contact with the wet paper X.

[0036] In the press part P, the thermo camera 4 is placed in a position where it can capture an image of the surface of the papermaking felt 2. A suitable placement position will be described later. The thermo camera 4 is an infrared camera that visualizes infrared rays emitted from an object. Therefore, the image captured by the thermo camera 4 is what is known as thermography. The thermo camera 4 is connected to the control device 5 by wire or wirelessly. Details of the control device 5 will be described later.

[0037] In the press part P, the washing device 6 consists of a first washing device 6a and a second washing device 6b. In the washing device 6, the first washing device 6a is arranged upstream with respect to the conveying direction of the papermaking felt 2, and the second washing device 6b is arranged downstream of the first washing device 6a. In addition, it is preferable that the first washing device 6a is also arranged downstream of the second washing device 6b.

[0038] Here, the first cleaning device 6a is a so-called wetting shower that sprays cleaning water at low pressure. This allows the cleaning liquid to be applied to the entire papermaking felt 2. The second cleaning device 6b is a so-called high-pressure sliding shower that sprays cleaning water at high pressure. This allows loose fine fibers in the papermaking felt 2 and contaminants such as pitch to be separated from the papermaking felt 2. Water is used as the cleaning water. The cleaning water may also contain a surfactant or the like that has a cleaning effect.

[0039] In the press part P, the suction box 7 is arranged downstream of the cleaning device 6 and the spraying device 8 with respect to the transport of the papermaking felt 2. In other words, the cleaning device 6 and the spraying device 8 are arranged upstream of the suction box 7. The suction box 7 sucks up the cleaning water and chemicals applied to the papermaking felt 2. At this time, the separated fine fibers and contaminants are also sucked in. In this way, the papermaking felt 2 is cleaned.

[0040] In the press part P, the spray device 8 is arranged downstream of the cleaning device 6 with respect to the transport of the papermaking felt 2. That is, from the upstream side, the cleaning device 6, the spray device 8, and the suction box 7 are arranged in this order. The spray device 8 has a rail portion (not shown) extending in the width direction of the wet paper, and a main body portion (not shown) that can slide back and forth along the rail. The main body portion has a plurality of nozzle holes (not shown) from which the chemical solution can be sprayed. Therefore, the spray device 8 can apply the chemical solution to the entire width of the wet paper by spraying the chemical solution while sliding the main body portion.

[0041] The chemical solution preferably contains a surfactant, a water-soluble polymer, and water. In this case, pitch, which causes clogging of the papermaking felt 2, can be effectively removed. Furthermore, from the viewpoint of dispersing pitch without affecting the wet paper, the surfactant is preferably an anionic surfactant or a nonionic surfactant, and a nonionic surfactant is more preferable. On the other hand, from the viewpoint of adsorbing and removing pitch, the water-soluble polymer is preferably a cationic polymer or an amphoteric polymer, and a cationic polymer is more preferable. Note that a chemical solution containing a surfactant, a water-soluble polymer, and water can effectively remove pitch, which causes clogging of the papermaking wire 1. In other words, a chemical solution with such a composition is effective on the papermaking wire 1 as well, and can effectively remove pitch regardless of the papermaking tool.

[0042] In the press part P, these processes are repeatedly performed on the papermaking felt 2. Specifically, in the press part P, one cycle is performed repeatedly in the following order: a first step of pressing an arbitrary point on the papermaking felt 2 together with the wet paper X by the press roll 3, and then separating the point from the wet paper X, a second step of performing a cleaning process by the first cleaning device 6a and the second cleaning device 6b, a third step of applying a chemical solution by the spray device 8, a fourth step of performing a suction process by the suction box 7, and a fifth step of contacting the point with the wet paper X.

[0043] In the press part P, the thermo camera 4 is preferably positioned upstream of the cleaning device 6 and the spraying device 8, or downstream of the suction box 7, relative to the transport of the papermaking felt 2. In this case, it is possible to minimize the influence of the cleaning device 6 spraying cleaning water or chemicals onto the papermaking felt 2. In the monitoring system shown in Figure 1, the thermo camera 4 is positioned in a part of the papermaking felt 2 that is not in contact with the wet paper X, downstream of the suction box 7, so as to face the papermaking felt 2.

[0044] Next, an example of monitoring the papermaking wire 1 (papermaking tool) in the wire part W (wet part WP) will be described. The wire part W has the papermaking wire 1 on which stock is loaded and excess water is allowed to fall naturally to form a wet paper, multiple wire rolls 1a for guiding the papermaking wire 1, a thermal camera 4 for capturing images of the papermaking wire 1, a control device 5 connected to the thermal camera 4, a washing device 6 for performing a washing process in which washing water is sprayed onto the papermaking wire 1 to wash it, a suction box 7 for performing a suction process in which the washing water is sucked in, and a spraying device 8 for spraying a chemical solution onto the papermaking wire 1.

[0045] In the wire part W, the papermaking wire 1 is an endless mesh sheet with fine mesh, and is guided by multiple wire rolls 1a. In the wire part W, the paper stock, which is the raw material for paper, is placed on the papermaking wire 1, and the papermaking wire 1 transports it while allowing excess water to fall through the mesh, thereby forming a wet paper X.

[0046] Here, single weave wires, 1.5-ply weave wires, double weave wires, 2.5-ply weave wires, triple weave wires, 3.5-ply weave wires, 3 / 1 collapsible weave wires, 2 / 2 diagonal weave wires, etc. can be used as the papermaking wire 1. Among these, it is preferable to use single weave wires, 1.5-ply weave wires, double weave wires, 2.5-ply weave wires, triple weave wires, or 3.5-ply weave wires as the papermaking wire 1. These have the advantage that if a malfunction occurs, the water retention capacity changes significantly, so that malfunctions can be easily detected by the monitoring system of the present invention.

[0047] In the wire part W, the thermo camera 4, the cleaning device 6, the suction box 7 and the spray device 8 are all installed so as to face the papermaking wire 1 when it is not in contact with the stock or wet paper X. It is also preferable that these are arranged so as to face the surface of the papermaking wire 1 that comes into contact with the stock or wet paper X. The thermo camera 4, the cleaning device 6, the suction box 7 and the spray device 8 are the same as those used in the press part P, so detailed explanations will be omitted.

[0048] In the wire part W, the cleaning device 6, the spray device 8, and the suction box 7 are arranged in this order from the upstream side with respect to the transport of the papermaking wire 1. Therefore, in the wire part W, one cycle is performed repeatedly in this order for any point on the papermaking wire 1: a first step of separating the point from the wet paper X, a second step of performing cleaning treatment with the first cleaning device 6a and the second cleaning device 6b, a third step of applying a chemical solution with the spray device 8, a fourth step of performing suction treatment with the suction box 7, and a fifth step of placing the paper stock.

[0049] In the wire part W, the thermo camera 4 is preferably positioned upstream of the cleaning device 6 and the spraying device 8, or downstream of the suction box 7, relative to the transport of the papermaking wire 1. In this case, it is possible to minimize the influence of the cleaning device 6 spraying cleaning water or chemicals onto the papermaking wire 1. In the monitoring system shown in Figure 1, the thermo camera 4 is positioned in a part of the papermaking wire 1 that is not in contact with the wet paper X, downstream of the suction box 7, so as to face the papermaking wire 1.

[0050] Next, the control device will be described. The control device will be described in terms of a case where a papermaking felt 2 is used as the papermaking tool. FIG. 2 is a block diagram illustrating the control device in the monitoring system according to this embodiment. As shown in FIG. 2, the control device 5 includes at least an imaging command issuing means 11 that issues an imaging command to the thermo camera 4 to capture an image, an acquisition means 12 that acquires a thermograph (see, for example, FIG. 4 ) captured by the thermo camera 4, a monitoring means 13 that monitors the state of the papermaking felt 2 (papermaking tool) based on the surface temperature of the papermaking felt 2 (papermaking tool) in the thermograph, and a spray command issuing means 16 that issues a chemical spray command to the spray device 8. The control device 5 is a computer in which a predetermined program is stored. The monitoring means 13 includes a first calculation means 14a, a first determination means 14b, a second calculation means 15a, and a second determination means 15b as specific means for performing monitoring. Details of these will be described later.

[0051] Fig. 3 is a flowchart showing the operation of the monitoring system according to this embodiment, and Fig. 4 is a photograph showing an example of a thermography image of a papermaking felt taken by a thermocamera in the monitoring system according to this embodiment. As shown in Fig. 3, in the control device 5, first, the imaging command issuing means 11 issues an imaging command to the thermocamera 4. In response, the thermocamera 4 images an arbitrary area of ​​the papermaking felt 2. Next, the acquisition means 12 acquires the thermography data as shown in Fig. 4 taken by the thermocamera 4.

[0052] Figure 5 is a graph of a temperature profile displaying values ​​calculated by the first calculation means using the thermography of the papermaking felt shown in Figure 4. The vertical axis of Figure 5 represents temperature (°C), and the horizontal axis represents position in the width direction L of the papermaking felt. As shown in Figure 5, in the monitoring means 13, the first calculation means 14a calculates the temperature of each pixel (picture element) in the width direction L at any position on the papermaking felt 2, based on the surface temperature of the papermaking felt 2 in the thermography shown in Figure 4. It also calculates the average temperature T of these temperatures. It then calculates the temperature difference between the temperature of each pixel in the width direction L at any position on the papermaking felt 2 during operation and the average temperature T of these temperatures.

[0053] Returning to FIG. 3 , in the monitoring means 13, the first judgment means 14b judges whether the temperature difference is within the range of a preset first threshold value Th1. That is, the first judgment means 14b monitors the state of the papermaking felt 2. Here, the first threshold value Th1 can be set arbitrarily depending on the material of the papermaking felt 2, processing conditions, empirical rules, etc. Positions outside the range of the first threshold value Th1 are judged as "abnormal," and positions within the range are judged as "normal." The thermography, temperature, average temperature, temperature difference, judgment results, etc. are stored in memory means (not shown) and can be retrieved at any time. These are also displayed appropriately on a display means (not shown) such as a monitor.

[0054] 5, the first threshold value Th1 is set to a range of 36.5° C. to 38.5° C. As a result, "abnormalities" that are outside the range of the first threshold value Th1 occur at the left end, center, and right end.

[0055] If the first determination means 14b determines that all the temperature differences for each pixel in the width direction L are "normal," processing continues in the press part P. On the other hand, if there is a position determined to be "abnormal," that is, if the first determination means 14b determines that the temperature difference at a predetermined position on the papermaking felt 2 is outside the range of the first threshold value Th1, it is possible to select whether or not to take measures.

[0056] Such measures include replacing the papermaking felt 2, intensive cleaning of the position of the papermaking felt 2 where the "abnormality" has occurred, spraying a chemical solution at the position of the papermaking felt 2 where the "abnormality" has occurred, or increasing the amount of chemical solution sprayed at the position of the papermaking felt 2 where the "abnormality" has occurred. When the first determination means 14b determines that the temperature difference at a predetermined position of the papermaking felt 2 is outside the range of the first threshold value Th1 and when spraying of a chemical solution or an increase in the amount of chemical solution sprayed is selected, the spray command issuing means 16 of the control device 5 issues a spray command to the spray device 8. In response to this, the spray device 8 sprays the chemical solution at the predetermined position, or sprays the chemical solution at the predetermined position by increasing the amount of chemical solution sprayed.

[0057] Here, if the temperature of the water supplied to the papermaking felt 2 during dehydration of the wet paper is lower than the ambient temperature and the temperature at the position determined to be abnormal is higher than the upper limit of the first threshold range, this means that the water retention capacity is lower than average. A possible cause of the lower water retention capacity is that the water permeability is high, and the mesh has become coarse due to shedding of fibers. Therefore, in this case, measures can be taken to replace the papermaking felt 2. On the other hand, if the temperature of the water supplied to the papermaking felt 2 during dehydration of the wet paper is lower than the ambient temperature and the temperature at the position determined to be abnormal is lower than the lower limit of the first threshold range, this means that the water retention capacity is higher than average. A possible cause of the higher water retention capacity is that the water permeability is low, and clogging due to dirt, etc. Therefore, in this case, measures can be taken such as intensive cleaning of the position where the ``abnormality'' has occurred on the papermaking felt 2, spraying a chemical solution on the position where the ``abnormality'' has occurred on the papermaking felt 2, or increasing the amount of chemical solution sprayed on the position where the ``abnormality'' has occurred on the papermaking felt 2.

[0058] Furthermore, if the temperature of the water supplied to the papermaking felt 2 during dehydration of the wet paper is higher than the ambient temperature and the temperature at the position determined to be abnormal is higher than the upper limit of the first threshold range, this means that the water retention capacity is higher than average. A possible cause of the increased water retention capacity is clogging due to dirt or other factors, as the water permeability is reduced. Therefore, in this case, measures can be taken, such as intensive cleaning of the position where the "abnormality" occurred on the papermaking felt 2, spraying a chemical solution on the position where the "abnormality" occurred on the papermaking felt 2, or increasing the amount of chemical solution sprayed on the position where the "abnormality" occurred on the papermaking felt 2. On the other hand, if the temperature of the water supplied to the papermaking felt 2 during dehydration of the wet paper is higher than the ambient temperature and the temperature at the position determined to be abnormal is lower than the lower limit of the first threshold range, this means that the water retention capacity is lower than average. A possible cause of the decreased water retention capacity is coarseness due to shedding of fibers, as the water permeability is increased. Therefore, in this case, measures can be taken to replace the papermaking felt 2.

[0059] In this way, by providing the first determination means 14a and the first determination means 14b, the monitoring system can recognize the degree of fiber loss and the degree of dirt adhesion at any position in the width direction L of the papermaking felt 2. Incidentally, the level of the average temperature is largely dependent on the operating environment. Therefore, in order to eliminate the influence of the environment as much as possible, the temperature is determined by calculating the temperature difference between the temperature of each pixel and the average temperature.

[0060] Figure 6 is a table showing the results of thermography taken over time at the same position in the width direction L of the papermaking felt shown in Figure 4. The vertical axis of Figure 6 represents the position in the width direction L of the papermaking felt, and the horizontal axis represents the actual measurement date; all images were taken at 3:00 PM. In practice, the higher the temperature, the darker the red color. Holidays H (May 9-12, May 16-26, May 28, May 30-6 / 1, and June 13 and later) are days when the papermaking machine was not in operation, and therefore appear colorless, indicating low temperatures. As shown in Figure 6, the second calculation unit 15a in the monitoring unit 13 calculates the temperature for each pixel in the width direction L in multiple thermography images taken over time at the same position in the width direction L of the papermaking felt shown in Figure 4. The degree of temperature change is then calculated from these temperatures.

[0061] Returning to FIG. 3 , in the monitoring means 13, the second judgment means 15b judges whether the degree of temperature change is within a preset second threshold range. That is, the second judgment means 15b monitors the state of the papermaking felt 2. Here, the second threshold can be set arbitrarily depending on the material of the papermaking felt 2, processing conditions, empirical rules, etc. Positions outside the second threshold range are judged as "abnormal," and positions within the second threshold range are judged as "normal" (see FIG. 6 ). Multiple thermographs, temperatures, degrees of temperature change, judgment results, etc. are stored in memory means (not shown) and can be retrieved at any time. These are also displayed appropriately on a display means (not shown) such as a monitor.

[0062] In Figure 6, a temperature rise is observed at a predetermined position (near the center) of the papermaking felt (area surrounded by a dotted line) from June 9 to June 13. On June 13, the temperature exceeded the upper limit of the range of the second threshold, so operation was stopped.

[0063] If the second determination means 15b determines that the degree of temperature change for each pixel in the width direction L is all "normal," processing continues in the press part P. On the other hand, if there is a position determined to be "abnormal," that is, if the second determination means 15b determines that the degree of temperature change at a predetermined position on the papermaking felt 2 is outside the range of the second threshold, it is possible to select whether or not to take measures.

[0064] Such measures include replacing the papermaking felt 2, intensive cleaning of the position of the papermaking felt 2 where the "abnormality" has occurred, spraying a chemical solution at the position of the papermaking felt 2 where the "abnormality" has occurred, or increasing the amount of chemical solution sprayed at the position of the papermaking felt 2 where the "abnormality" has occurred. When the second determination means 15b determines that the degree of temperature change at a predetermined position of the papermaking felt 2 is outside the range of the second threshold value and spraying of a chemical solution or increasing the amount of chemical solution sprayed is selected, the spray command issuing means 16 of the control device 5 issues a spray command to the spray device 8. In response to this, the spray device 8 sprays the chemical solution at the predetermined position, or sprays the chemical solution at the predetermined position by increasing the amount of chemical solution sprayed.

[0065] Here, if the temperature of the water supplied to the papermaking felt 2 due to the dehydration of the wet paper is lower than the ambient temperature and the temperature change at the position determined to be abnormal is greater than the upper limit of the second threshold range, this means that the water retention capacity is lower than average. A possible cause of the reduced water retention capacity is that the water permeability is high, and the mesh has become coarse due to shedding of fibers. Therefore, in this case, measures can be taken to replace the papermaking felt 2. On the other hand, if the temperature of the water supplied to the papermaking felt 2 due to the dehydration of the wet paper is lower than the ambient temperature and the temperature change at the position determined to be abnormal is smaller than the lower limit of the second threshold range, this means that the water retention capacity is higher than average. A possible cause of the increased water retention capacity is that the water permeability is low, and clogging due to dirt, etc. Therefore, in this case, measures can be taken such as intensive cleaning of the position where the ``abnormality'' has occurred on the papermaking felt 2, spraying a chemical solution on the position where the ``abnormality'' has occurred on the papermaking felt 2, or increasing the amount of chemical solution sprayed on the position where the ``abnormality'' has occurred on the papermaking felt 2.

[0066] Furthermore, if the temperature of the water supplied to the papermaking felt 2 during dehydration of the wet paper is higher than the ambient temperature and the temperature change at the position determined to be abnormal is greater than the upper limit of the second threshold range, this means that the water retention capacity is higher than average. A possible cause of the increased water retention capacity is clogging due to dirt or other factors, as the water permeability is reduced. Therefore, in this case, measures can be taken, such as intensive cleaning of the position where the "abnormality" occurred on the papermaking felt 2, spraying a chemical solution at the position where the "abnormality" occurred on the papermaking felt 2, or increasing the amount of chemical solution sprayed at the position where the "abnormality" occurred on the papermaking felt 2. On the other hand, if the temperature of the water supplied to the papermaking felt 2 during dehydration of the wet paper is higher than the ambient temperature and the temperature change at the position determined to be abnormal is smaller than the lower limit of the second threshold range, this means that the water retention capacity is lower than average. A possible cause of the decreased water retention capacity is coarseness due to shedding of fibers, as the water permeability is increased. Therefore, in this case, measures can be taken to replace the papermaking felt 2.

[0067] In this way, by providing the second determination means 15a and the second determination means 15b, the monitoring system can recognize the degree of fiber loss and the degree of dirt adhesion over time at any position in the width direction L of the papermaking felt 2. Furthermore, since the monitoring means can predict the timing at which a problem will occur in the papermaking felt 2, it becomes possible to review the processing conditions of the press part P and prepare in advance for the replacement of the papermaking felt 2.

[0068] The monitoring system according to this embodiment is a system for monitoring the condition of papermaking tools (papermaking felt 2 or papermaking wire 1) in the wet part of the papermaking process. In the present invention, the papermaking machine includes a dry part, a reel part, and the like in addition to the wet part WP described above. The monitoring system makes it possible to recognize when a malfunction occurs in a papermaking tool during operation and when the severity of the malfunction gradually increases. Therefore, by using the monitoring system, countermeasures can be taken before the malfunction of the papermaking tool prevents the tool from fully performing its function. Furthermore, taking countermeasures can at least delay the occurrence of the malfunction, allowing the papermaking tool to be replaced before the malfunction occurs. As a result, a significant decrease in yield due to the occurrence of a malfunction can be prevented.

[0069] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above embodiments.

[0070] The monitoring system according to this embodiment shows an example of a wet part WP in a multi-cylinder papermaking machine for producing paperboard (medium), but is not limited to this. Figures 7 and 8 are schematic side views showing a wet part in which a monitoring system according to another embodiment is used. As shown in Figure 7, the monitoring system can also be applied to a wet part WP1 in a household papermaking machine for producing household paper. The wet part WP1 of the household papermaking machine uses one endless papermaking wire 1 and one endless papermaking felt 2. As with the monitoring system according to this embodiment, a thermal camera 4, a cleaning device 6, a suction box 7, and a spraying device 8 are installed for the papermaking wire 1 and the papermaking felt 2, respectively.

[0071] 8, the monitoring system can also be used in the wet part WP2 of a papermaking machine used to manufacture paper. The wet part of the papermaking machine uses one endless papermaking wire 1 and three endless papermaking felts. As with the monitoring system of this embodiment, a thermal camera 4, a cleaning device 6, a suction box 7, and a spraying device 8 are installed for the papermaking wire 1 and the papermaking felt 2, respectively.

[0072] In the monitoring system according to this embodiment shown in FIG. 1, the third papermaking felt 2c and the fourth papermaking felt 2d do not have a thermo camera 4, a cleaning device 6, a suction box 7 and a spray device 8, but as with the first papermaking felt 2a, the thermo camera 4, the cleaning device 6, the suction box 7 and the spray device 8 may be installed at opposing positions.

[0073] In the monitoring system according to this embodiment, a thermo camera 4, a cleaning device 6, a suction box 7, and a spray device 8 are installed facing the papermaking felt 2, but a plurality of each of these may be installed for one papermaking felt 2. In other words, the papermaking felt 2 may be monitored at a plurality of locations. Note that the dotted lines in Figure 1 show an example of the positions where a plurality of thermo cameras 4a are installed.

[0074] In the monitoring system according to this embodiment, a doctor for physically scraping off dirt adhering to the guide roll and a doctor shower for cleaning the doctor may be installed near the guide roll that guides the papermaking felt 2.

[0075] In the monitoring system according to this embodiment, the cleaning device 6 is composed of a first cleaning device 6a and a second cleaning device 6b, but it may be only one of them, or it may have an additional cleaning device.

[0076] In the monitoring system according to this embodiment, the spraying device 8 comprises a rail portion and a main body portion, and the chemical solution is sprayed while the main body portion is slid, but the structure of the spraying device 8 is not limited to this. For example, the spraying device may have a structure in which a plurality of nozzle holes are provided in a pipe extending in the width direction of the papermaking tool, and the chemical solution is applied simultaneously from each nozzle hole to the entire width of the papermaking tool.

[0077] In the monitoring system according to this embodiment, the cleaning device 6, the spray device 8, the suction box 7, and the spray device 8 are arranged in the wet part, but these are not essential. For example, only the cleaning device 6 and the suction box 7 may be arranged, or only the spray device 8 and the suction box 7 may be arranged. Furthermore, the positions of the spray device 8 and the cleaning device 6 may be reversed.

[0078] In the monitoring system for the papermaking felt 2 according to this embodiment, the control device 5 includes an imaging command issuing means 11, an acquisition means 12, a monitoring means 13, a spray command issuing means 16, a storage means, and a display means, and may further include an input means such as a general mouse. Also, if the system does not have the spray device 8, the spray command issuing means 16 may not be included.

[0079] In the monitoring system according to this embodiment, the monitoring means 13 includes the first calculation means 14a, the first determination means 14b, the second calculation means 15a, and the second determination means 15b as specific means for performing monitoring, but may include only the first calculation means 14a and the first determination means 14b, or may include only the second calculation means 15a and the second determination means 15b. Alternatively, the monitoring means 13 may further include another monitoring means.

[0080] In the monitoring system according to this embodiment, the chemical solution contains a surfactant, a water-soluble polymer, and water, but this is not essential. When the papermaking tool is a papermaking felt 2, the chemical solution preferably contains at least a surfactant and water. When the papermaking tool is a papermaking wire 1, the chemical solution preferably contains at least a water-soluble polymer and water. In addition to these, the chemical solution may also contain additives such as a chelating agent, a pH adjuster, a preservative, a viscosity adjuster, a solid lubricant, a wetting agent, an anti-dusting agent, a release agent, an adhesive, a surface modifier, a paper strength agent, a sizing agent, a retention aid, an anti-slip agent, and a softener.

[0081] The monitoring system of the present invention can be used as a system for monitoring the condition of papermaking tools used in the wet part. By monitoring the condition of papermaking tools during operation, the monitoring system of the present invention can prevent malfunctions from occurring. This makes it possible to suppress a decrease in yield due to malfunctions of papermaking tools.

[0082] DESCRIPTION OF SYMBOLS 1...Papermaking wire 1a...Wire roll 11...Image capture command issuing means 12...Acquisition means 13...Monitoring means 14a...First calculation means 14b...First judgment means 15a...Second calculation means 15b...Second judgment means 16...Blowing command issuing means 2...Papermaking felt 2a...First papermaking felt 2b...Second papermaking felt 2c...Third papermaking felt 2d...Fourth papermaking felt 3...Press roll 3a...Upstream press roll 3a1...First top roll 3a2...Second bottom roll 3b...Downstream press roll 3b1...Second top roll 3b2...Second bottom roll 4...Thermo camera 5...Control device 6...Cleaning device 6a...First cleaning device 6b...Second cleaning device 7...Suction box 8...Blowing device P...Press part W...Wire part WP, WP1, WP2...Wet part X...Wet paper

Claims

1. A monitoring system for monitoring the condition of papermaking tools used in a wet part, wherein the wet part comprises at least the papermaking tools used in contact with a wet paper, a plurality of guide rolls for guiding the papermaking tools, a thermocamera for capturing images of the papermaking tools, and a control device to which the thermocamera is connected, wherein the papermaking tools are papermaking felt or papermaking wire, and the control device comprises: an imaging command sending means for sending an imaging command to the thermocamera, an acquisition means for acquiring a thermograph captured by the thermocamera, and a monitoring means for monitoring the condition of the papermaking tools based on the surface temperature of the papermaking tools in the thermograph.

2. A monitoring system as described in claim 1, wherein the monitoring means comprises: a calculation means for calculating the temperature difference between the temperature of each pixel in the width direction at any position of the papermaking tool in operation in the thermograph and the average temperature of these temperatures, and a judgment means for judging whether the temperature difference is within a preset threshold range, and the condition of the papermaking tool is monitored by the judgment means.

3. A monitoring system as described in claim 2, wherein the wet part further has a spraying device for spraying a chemical solution onto the papermaking tool, the control device further has a spray command issuing means for issuing a spray command to the spraying device to spray the chemical solution, and when the determination means determines that the temperature difference at a specified position on the papermaking tool is outside the threshold range, the spray command issuing means issues the spray command to the spraying device, and the spraying device sprays the chemical solution onto the specified position or increases the amount of the chemical solution sprayed onto the specified position.

4. A monitoring system as described in claim 1, wherein the monitoring means comprises: a calculation means for calculating the degree of temperature change over time for each pixel in the width direction at any position of the papermaking tool while in operation, based on the surface temperature of the papermaking tool in multiple thermographs acquired over time; and a judgment means for judging whether the degree of temperature change is within a preset threshold range, and the condition of the papermaking tool is monitored by the judgment means.

5. A monitoring system as described in claim 4, wherein the wet part further has a spray device for spraying a chemical solution onto the papermaking tool, the control device further has a spray command issuing means for issuing a command to the spray device to spray the chemical solution, and when the determination means determines that the degree of temperature change at a specified position on the papermaking tool is outside the range of the threshold, the spray command issuing means issues the spray command to the spray device, and the spray device sprays the chemical solution onto the specified position or increases the amount of the chemical solution sprayed onto the specified position.

6. A monitoring system as described in claim 1, wherein the monitoring means comprises: a first calculation means for calculating a temperature difference between the temperature of each pixel in the width direction at any position of the papermaking tool in operation in the thermograph and an average temperature of these temperatures, in the surface temperature of the papermaking tool in the thermograph; a first judgment means for judging whether the temperature difference is within a preset first threshold range; a second calculation means for calculating a degree of temperature change over time for each pixel in the width direction at any position of the papermaking tool in operation in the surface temperature of the papermaking tool in multiple thermographs acquired over time; and a second judgment means for judging whether the degree of temperature change is within a preset second threshold range, and the condition of the papermaking tool is monitored by the first judgment means and the second judgment means.

7. A monitoring system as described in claim 6, wherein the wet part further has a spray device for spraying a chemical solution onto the papermaking tool, and the control device further comprises a spray command issuing means for issuing a spray command to the spray device for the chemical solution, and when the first judgment means judges that the temperature difference at a specified position on the papermaking tool is outside the range of the first threshold value, or when the second judgment means judges that the degree of the temperature change at a specified position on the papermaking tool is outside the range of the second threshold value, the spray command issuing means issues the spray command to the spray device, and the spray device sprays the chemical solution onto the specified position or increases the amount of the chemical solution sprayed onto the specified position.

8. A monitoring system as claimed in any one of claims 3, 5 and 7, wherein, when the papermaking tool is the papermaking felt, the chemical solution contains at least a surfactant and water, the surfactant being an anionic surfactant or a nonionic surfactant, and when the papermaking tool is the papermaking wire, the chemical solution contains at least a water-soluble polymer and water, the water-soluble polymer being a cationic polymer or an amphoteric polymer.

9. A monitoring system as described in any one of claims 3, 5 and 7, wherein the chemical solution contains at least a surfactant, a water-soluble polymer and water, the surfactant is an anionic surfactant or a nonionic surfactant, and the water-soluble polymer is a cationic polymer or an amphoteric polymer.

10. A monitoring system according to claim 1, wherein the papermaking felt is a single-ply weave felt, a double-ply weave felt, a 2.5-ply weave felt or a triple-ply weave felt, and the papermaking wire is a single-ply weave wire, a 1.5-ply weave wire, a double-ply weave wire, a 2.5-ply weave wire, a triple-ply weave wire or a 3.5-ply weave wire.

11. A monitoring system as described in claim 1, wherein the wet part further comprises a cleaning device for performing a cleaning process by spraying cleaning water onto the papermaking tools to clean them, and a suction box for performing a suction process by sucking in the cleaning water, wherein the cleaning device is disposed upstream of the suction box with respect to the transport of the papermaking tools, and the thermo camera is disposed upstream of the cleaning device or downstream of the suction box.

Images