A method for controlling the tension of a paper strip in a leading paper roller

Abstract

The application relates to the papermaking technical field, in particular to a paper guiding and roll combining paper strip tension control method. The method comprises the following steps: controlling an auxiliary paper guiding device to guide the cut paper strip to a rear drying part and make the paper strip fall into a pulper; when a monitoring system detects that the paper strip falls into the pulper, controlling upper and lower sizing rollers of a sizing machine to close and size, and gradually adjusting a speed difference between the two sizing rollers and the rear drying part, so that the speed difference reaches a preset value when the sizing roller closing is completed; after the paper guiding device expands the paper strip to a full width, adjusting the speed difference between the upper and lower sizing rollers and the rear drying part according to real-time tension detected by a tension detection device. It can be seen that the paper guiding and roll combining paper strip tension control method can realize tension stable compensation in the whole paper guiding process, effectively reduces tension fluctuation and paper breakage risk when the sizing roller is closed, and improves paper guiding success rate, production efficiency and economic benefits.

Description

Technical Field

[0001] This application relates to the field of papermaking technology, and in particular to a method for controlling the tension of paper strips on the paper feed roller. Background Technology

[0002] Sizing is a crucial process in papermaking, using sizing agents to impart water resistance, surface strength, and printability to the paper. Based on different sizing principles, it can be divided into two types: in-pulp sizing and surface sizing. Surface sizing involves applying a sizing agent to the paper surface after the base paper has dried, forming a continuous adhesive layer that improves the paper's physical strength, surface strength, and water resistance. The sizing machine is the core equipment for surface sizing, consisting of an upper and lower sizing roller, positioned opposite each other to form a pressure zone. Starch adhesive is evenly transferred to the surface of the sizing rollers via a metering rod. As the paper sheet passes through the pressure zone between the two rollers, the adhesive on the roller surface is transferred to the paper surface, completing the sizing process. The operational stability of the sizing machine directly affects paper quality and production efficiency. When feeding paper into the sizing machine, a narrow strip of paper needs to be guided from the front of the sizing machine to the rear drying section via a paper feeding device, allowing the paper strip to pass between the upper and lower sizing rollers. Then, with the assistance of a blower and paper feeding rope, the paper strip is pulled and blown to the pulper below. Finally, the two sizing rollers are closed to allow the paper strip to enter normal operation. However, when the two sizing rollers are closed, the sizing agent rapidly transfers to the paper strip, causing drastic changes in the temperature and humidity of the paper strip, which in turn leads to sharp fluctuations in the paper strip tension. These tension fluctuations can easily cause the paper strip to break, resulting in feeding failure.

[0003] In existing technologies, the paper feeding process of a sizing machine is adjusted based on a fixed speed difference between the sizing roller and the post-drying section. However, the actual paper feeding process consists of three stages: paperless, sizing roller closure, and expansion. Each stage has different requirements for the speed difference, and a fixed speed difference cannot adapt to dynamic tension changes. Operators rely on experience to manually adjust the speed difference, which suffers from problems such as response lag, insufficient adjustment accuracy, and human cognitive differences. This results in the inability to compensate for tension fluctuations caused by the transfer of adhesive material when the sizing roller closes, easily leading to paper breakage, low paper feeding success rate, and seriously affecting production efficiency and economic benefits. Summary of the Invention

[0004] This application is made in view of the above-mentioned issues.

[0005] This application provides a method for controlling the tension of paper strips on a paper-feeding roller, applied to a papermaking system. The papermaking system includes at least a paper-feeding device, an auxiliary paper-feeding device, a post-drying section, a sizing machine, a pulper, a monitoring system, a tension detection device, and a control system. The paper-feeding device, the auxiliary paper-feeding device, the post-drying section, the sizing machine, the pulper, the monitoring system, and the tension detection device are all electrically connected to the control system. The sizing machine has an upper sizing roller and a lower sizing roller. The method includes:

[0006] The auxiliary paper feeding device guides the cut paper strips to the post-drying section and into the pulper; When the monitoring system detects that the cut paper strip to be glued falls into the pulper, it controls the upper and lower glue rollers of the gluer to close, and applies glue to the paper strip to be glued. At the same time, it gradually controls the speed difference between the upper and lower glue rollers and the post-drying section, so that the speed difference reaches a preset value when the upper and lower glue rollers are closed. After the paper feeding device expands the cut paper strip to its full width, the real-time tension detected by the tension detection device is obtained, and the speed difference between the upper and lower gluing rollers and the post-drying section is controlled based on the real-time tension.

[0007] Compared with the prior art, the paper tension control method of the paper feeding and closing roller provided in this application includes first controlling the auxiliary paper feeding device to guide the cut paper strip to be glued to the post-drying section and fall into the pulper. This can not only ensure that the paper strip arrives smoothly at the designated position before glue application, but also provide a monitorable start signal for the closing action of the subsequent glue application roller, avoiding the glue application operation to be started due to the paper strip not being delivered in place, which would lead to process problems such as paper strip jamming and paper breakage.

[0008] When the monitoring system detects that the cut paper strips to be glued have fallen into the pulper, it controls the two rollers to come together to form a pressure zone. As the paper strip passes through the pressure zone, the glue is applied. However, when the glue rollers are closing to apply glue, the glue will change the temperature and humidity of the paper strip, which can easily cause a sudden change in the paper strip tension, resulting in loosening or even paper breakage. Therefore, at the same time as the closing action is started, the control system will gradually adjust the transmission speed difference between the upper and lower glue rollers and the post-drying section, and ensure that at the point when the glue rollers are fully closed and the formal glue application is carried out, the speed difference reaches the preset value. This allows the narrow paper strip to maintain a suitable tension even without effective tension detection, avoiding paper breakage due to uncontrolled tension during the glue application process.

[0009] Once the paper feeding device expands the cut strip of paper to its full width, the paper web can completely and evenly adhere to the tension detection device, allowing the device to collect stable and effective real-time tension values. At this point, the control system no longer relies on preset values ​​to control the speed difference. Instead, it acquires the real-time tension detected by the tension detection device and dynamically adjusts the speed difference between the upper and lower gluing rollers and the post-drying section based on this real-time tension. If the real-time tension is too low, it indicates the paper web is too loose, so the speed difference is appropriately increased to tighten the paper web. If the real-time tension is too high, it indicates the paper web is too tight, so the speed difference is appropriately decreased to loosen the paper web. This ensures that the tension of the entire paper web is always maintained within the required process range, preventing wrinkles and paper breaks due to uneven tension, and ensuring that the adhesive is evenly coated across the entire paper web, thus improving the gluing quality.

[0010] Based on this, the paper tension control method of the paper strip of the paper feeding roller provided in this application can achieve stable tension compensation throughout the paper feeding process, effectively reduce tension fluctuations and paper breakage risk when the sizing roller is closed, and improve paper feeding success rate, production efficiency and economic benefits.

[0011] It should be understood that both the foregoing general description and the following detailed description are exemplary and intended to provide further illustration of the claimed technology. Attached Figure Description

[0012] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments of this application in conjunction with the accompanying drawings. The accompanying drawings are used to provide a further understanding of the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain this application and do not constitute a limitation thereof. In the accompanying drawings, the same reference numerals generally represent the same components or steps.

[0013] Figure 1 A schematic diagram of the structure of a papermaking system according to an embodiment of this application is shown; Figure 2 The diagram shows the electrical connection relationship of the papermaking system according to an embodiment of this application; Figure 3 A flowchart of the paper strip tension control method of the paper feed roller according to an embodiment of this application is shown; Figure 4 A flowchart illustrating a method for progressively controlling the speed difference between the upper and lower glue rollers and the post-drying section according to an embodiment of this application is shown. Detailed Implementation

[0014] To make the objectives, technical solutions, and advantages of this application more apparent, exemplary embodiments according to this application will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments of this application. It should be understood that this application is not limited to the exemplary embodiments described herein.

[0015] Sizing is a crucial process in papermaking, using sizing agents to impart water resistance to paper while simultaneously improving its surface strength and printability. Based on different sizing principles, it can be divided into two types: in-pulp sizing and surface sizing. Surface sizing involves applying a sizing agent to the paper surface after the base paper has dried, forming a continuous adhesive layer that enhances the paper's physical strength, surface strength, and water resistance. Figure 1 A schematic diagram of the papermaking system according to an embodiment of this application is shown. Figure 1As shown, the sizing machine 101 is the core equipment for surface sizing, featuring an upper sizing roller 1011 and a lower sizing roller 1012, which are arranged opposite each other to form a pressure zone. Starch adhesive is evenly transferred to the surface of the sizing rollers via a metering rod. When the paper passes through the pressure zone between the upper and lower sizing rollers, the adhesive on the rollers is transferred to the paper surface, completing the sizing process. The operational stability of the sizing machine 101 directly affects paper quality and production efficiency. When the sizing machine 101 feeds paper, the paper feeding device 102 first guides the narrow strip of paper from the front of the sizing machine 101 to the rear drying section 103, allowing the paper strip to pass between the upper and lower sizing rollers 1011 and 1012. During this process, a suspended steering device 104 located in front of the sizing machine changes the direction of the paper web while maintaining paper web stability and preventing wrinkles. Next, the auxiliary paper-feeding device 105, namely the blower plate 1051 and the paper-feeding rope 1052, assists in pulling the paper strip and blowing it along the waste paper conveying device 106 to the pulper 107 below. Finally, the two upper sizing rollers 1011 and the lower sizing roller 1012 are closed to bring the paper strip into normal operation. However, when the two sizing rollers are closed, the sizing agent is rapidly transferred to the paper strip, causing drastic changes in the temperature and humidity of the paper strip, which in turn causes a sharp fluctuation in the paper strip tension. This tension fluctuation can easily lead to paper strip breakage, resulting in paper-feeding failure.

[0016] In existing technology, the paper feeding process of a sizing machine is adjusted based on a fixed speed difference between the sizing roller and the post-drying section. However, the actual paper feeding process is divided into three stages: no paper, sizing roller closure, and expansion. Each stage has different requirements for the speed difference, and a fixed speed difference cannot adapt to dynamic changes in tension. Operators rely on experience to manually adjust the speed difference, which has problems such as response lag, insufficient adjustment accuracy, and differences in human perception. If a paper break occurs during this process, the paper feeding needle before sizing needs to be repositioned to the paper feeding strip position. This process takes 1 minute to repeat. For a high-speed paper machine with a capacity of about 1 ton per minute, each repetition of this process reduces the capacity by about 1 ton. Assuming 400 paper breaks per year, with each paper feeding requiring two attempts, 400 × 2 = 800 tons, resulting in an annual capacity reduction of 800 tons. Based on a sales price of 6,000 yuan per ton of paper, this translates to a reduction in sales revenue of approximately 4.8 million yuan.

[0017] Figure 2 A diagram showing the electrical connections of a papermaking system according to an embodiment of this application is illustrated. Figure 1 and Figure 2 As shown, the papermaking system includes at least a paper feeding device 102, an auxiliary paper feeding device 105, a post-drying section 103, a sizing machine 101, a pulper 107, a monitoring system 108, and a tension detection device 109, all of which are electrically connected to the control system 110. The sizing machine 101 has an upper sizing roller 1011 and a lower sizing roller 1012. Furthermore, the suspended steering device 104 and the waste paper conveying device 106 are also electrically connected to the control system 110.

[0018] It should be understood that the papermaking system can be a high-speed cultural paper machine system, or a commercially available high-speed cultural paper machine. The monitoring system is used to monitor the position of the paper feeding device, the traction status of the auxiliary paper feeding device, the working status of the sizing machine, and whether the pulper is in operation. The working status of the sizing machine includes whether the upper and lower sizing beams are closed, whether the upper and lower sizing rollers are closed, and whether the sizing machine is in a feeding state. The control system is used to control changes in the position of the paper feeding water needle, changes in the traction status of the paper feeding rope, and changes in the working status of the sizing machine. The tension detection device is used to detect the actual tension of the paper web in real time and transmit the detected real-time tension signal to the control system, providing feedback signals to the control system. It is understood that all components of the papermaking system in this application embodiment are prior art, and all components used are commercially available. This application only improves the method; therefore, the specific structure of the papermaking system is not limited.

[0019] To address the aforementioned issues, this application provides a paper tension control method for the paper strip on the paper feeding roller, which can achieve stable tension compensation throughout the paper feeding process, effectively reducing tension fluctuations and paper breakage risks during the closing of the sizing roller, and improving paper feeding success rate, production efficiency, and economic benefits. Figure 3 A flowchart illustrating the paper strip tension control method of the paper feed roller according to an embodiment of this application is shown. Figure 3 As shown, the method includes: S301: Control the auxiliary paper feeding device to guide the cut paper strips to be glued to the post-drying section and fall into the pulper.

[0020] For example, this step can ensure that the paper strip arrives smoothly at the designated position before gluing, and can also provide a monitorable start signal for the subsequent closing action of the gluing roller, avoiding the gluing operation from starting due to the paper strip not being delivered in place, which would lead to process problems such as paper strip jamming and paper breakage.

[0021] Exemplarily, the auxiliary paper guiding device in this application embodiment includes a paper guiding rope and a blowing plate electrically connected to the control system; the post-drying section includes multiple sets of drying cylinders arranged along the paper web running direction. Specifically, this step includes: First, the paper guide rope is controlled to pull the strip of paper to be sized to the first set of drying cylinders along the paper web running direction. This allows the strip to move along the multiple drying cylinders towards the last set along the paper web running direction, thus preventing the strip from shifting, wrinkling, or breaking during transport. Next, when the strip reaches the last set of drying cylinders along the paper web running direction, the blower plate is controlled to blow the strip into the pulper.

[0022] For example, the paper guiding device includes a paper guiding water needle electrically connected to the control system. Before this step, the method further includes: controlling the paper guiding water needle to cut the paper web into a strip to be glued, the strip being 30cm to 40cm wide, ensuring that the strip can be smoothly drawn and passed through the sizing machine and the post-drying section, and finally smoothly enter the pulper. When controlling the paper guiding water needle to cut the paper web, the cutting pressure is 300bar to 600bar to ensure a stable paper web cutting process and a neat cut, avoiding paper strip breakage, etc., laying a stable foundation for subsequent sizing roll closure, speed difference adjustment and tension control, and ensuring that the paper guiding and closing roll process can proceed in an orderly manner.

[0023] Understandably, the post-drying section comprises multiple sets of drying cylinders arranged sequentially along the paper web's running direction. The paper guide rope is positioned on the paper web's running path between the sizing machine and the first set of drying cylinders in the post-drying section. The blower plate is positioned downstream of the last set of drying cylinders in the post-drying section along the paper web's running direction, and above the pulper. The pulper is arranged directly below the blower plate, forming a corresponding vertical support layout. The paper guide rope, the multiple sets of drying cylinders in the post-drying section, the blower plate, and the pulper are sequentially connected along the paper web's running direction, together forming a complete conveying channel for the paper strips to be sized. The paper guide water needle is positioned upstream in the paper web's running direction, in front of the sizing machine, the post-drying section, and the pulper. This layout ensures that the paper guide water needle completes its cutting action before the paper web enters the sizing machine. It should be understood that the paper guiding device in the embodiments of this application is any kind of paper guiding device in the prior art, which includes other components in addition to the paper guiding water needle, and is not limited here.

[0024] S302: When the monitoring system detects that the cut paper strips to be glued fall into the pulper, it controls the upper and lower glue rollers of the gluer to close, applies glue to the paper strips to be glued, and at the same time gradually controls the speed difference between the upper and lower glue rollers and the post-drying section, so that the speed difference reaches the preset value when the upper and lower glue rollers are closed.

[0025] For example, at the same time as the closing roller action is started, the control system will gradually adjust the transmission speed difference between the upper and lower glue rollers and the post-drying section, and ensure that the speed difference reaches the preset value at the node when the glue roller is fully closed and formal glue application is carried out. This allows the narrow paper strip to maintain a suitable tension without effective tension detection, and avoids paper breakage due to uncontrolled tension during the glue application process.

[0026] For example, the glue applicator also has an upper glue applicator beam and a lower glue applicator beam. The upper glue applicator beam is located on the paper feed side of the upper glue applicator roller, and the lower glue applicator beam is located on the paper feed side of the lower glue applicator roller. Metering bars are provided on both the upper glue applicator roller and the lower glue applicator roller.

[0027] Understandably, both the upper and lower sizing beams are components of the sizing machine. The upper sizing beam is located on the paper feed side of the upper sizing roller, and the lower sizing beam is located on the paper feed side of the lower sizing roller. Both are situated upstream of the pressure zone between the upper and lower sizing rollers as the paper strip to be sizing enters. Metering rods are installed on both the upper and lower sizing rollers. The upper and lower sizing beams, as well as the metering rods, are electrically connected to the control system of the papermaking system. The control system uniformly controls the closing of the sizing beams, the setting of the sizing pressure, the monitoring of the feeding flow rate, and the setting of the metering rod pressure. The entire set of components is arranged in the main structure of the sizing machine downstream of the paper feeding device and upstream of the post-drying section, and is used to complete the feeding and pressurization preparation work before the upper and lower sizing rollers close.

[0028] The method further includes, before controlling the closing of the upper and lower application rollers of the glue applicator: By controlling the closure of the upper and lower glue application beams and setting the glue application pressure of the upper and lower glue application beams to 4KN / m, the glue application beams can be tightly fitted with the corresponding glue application rollers, ensuring a stable glue supply.

[0029] When the feeding flow rate of the upper and lower gluing beams reaches 1100L / min~1200L / min, the pressure of the metering rods of the upper and lower gluing rollers is set to 160kPa~170kPa. This can evenly distribute the glue on the surface of the gluing rollers, ensuring a uniform and stable glue layer distribution. This prepares the rollers for subsequent closure and normal gluing of the paper strips to be glued, ensuring a stable and reliable gluing process.

[0030] S303: After the paper feeding device expands the cut paper strip to be glued to the full width, the real-time tension detected by the tension detection device is obtained, and the speed difference between the upper and lower glue rollers and the post-drying section is controlled based on the real-time tension.

[0031] For example, after the paper feeding device expands the cut strip of paper to be glued to its full width, the paper web can completely and evenly adhere to the tension detection device, allowing the detection device to collect stable and effective real-time tension values. At this time, the control system no longer relies on preset values ​​to control the speed difference, but instead obtains the real-time tension detected by the tension detection device and dynamically adjusts the speed difference between the upper and lower glue rollers and the post-drying section based on this real-time tension. If the real-time tension is too low, it indicates that the paper web is too loose, so the speed difference is appropriately increased to tighten the paper web; if the real-time tension is too high, it indicates that the paper web is too tight, so the speed difference is appropriately decreased to loosen the paper web. This ensures that the tension of the entire paper web is always maintained within the range required by the process, avoiding wrinkles and paper breaks due to uneven tension, and ensuring that the glue is evenly coated on the entire paper web, thus improving the glue application quality.

[0032] For example, the paper-feeding needle includes a drive-side paper-feeding needle and an operating-side paper-feeding needle. The paper-feeding device extends the cut strip of paper to be glued to its full width, including: Control the paper-feeding needles on the drive side to move towards the drive side of the sizing machine, and control the paper-feeding needles on the operating side to move towards the operating side of the sizing machine, so as to expand the cut paper strips to be sizing to the full width.

[0033] Figure 4 A flowchart illustrating a method for progressively controlling the speed difference between the upper and lower glue application rollers and the post-drying section, according to an embodiment of this application, is shown. Figure 4 As shown, the method includes: S401: Control the speed difference between the upper and lower glue application rollers and the first set of drying cylinders in the rear drying section, so that the speed difference reaches the preset value when the upper and lower glue application rollers are closed.

[0034] For example, the preset value is 4 times the speed difference between the upper and lower gluing rollers and the first set of drying cylinders in the post-drying section under normal operating conditions of the gluing machine. This can adapt to the tension state of the paper strip during the paper feeding stage and avoid paper strip wrinkling, loosening or paper breakage caused by unreasonable speed difference.

[0035] Furthermore, the basis weight of the paper strip to be glued is 70 g / m². 2 ~80g / m 2 When the basis weight of the paper strip to be sized changes by ±10 g / m 2 At this time, the preset value is adjusted by ±0.5 times based on 4 times. During this process, the speed difference preset value is adjusted synchronously with the change of paper strip basis weight, which can ensure that paper strips with different basis weights are in a suitable tension state during the paper feeding and closing roller stage, avoiding paper strip slack, wrinkles or breakage, and improving the adaptability and stability of tension control.

[0036] S402: After maintaining the preset value for 10 seconds, adjust the speed difference to twice the normal operating speed difference until the paper strip to be glued expands to the full width.

[0037] For example, this step can prevent problems such as abnormal tension, wrinkling or breakage of the paper strip caused by sudden changes in speed difference, and provide a stable tension environment for the transition of the paper strip from narrow-width drawing to full-width production.

[0038] It should be noted that the glue applicator has an operating side and a drive side. The drive side can be defined as the side of the glue applicator where the drive mechanism is located and where the drive action is performed. The operating side can be defined as the opposite side of the glue applicator, and it is mainly used for operation and maintenance. There can be two paper-feeding needles.

[0039] Furthermore, the control system in this application is a conventional existing control system in the papermaking industry, mainly including a controller, a signal receiving unit, an execution control unit, and a control panel. The signal receiving unit receives various detection signals from the monitoring system, such as paper strip arrival signals, tension signals from the tension detection device, and material flow signals from the sizing beam, and transmits these signals to the controller. The controller, as the core, analyzes and processes the received signals to generate corresponding control commands. The execution control unit is electrically connected to equipment such as the paper feeding device, the post-drying section, the sizing machine, and the pulper, and executes the commands issued by the controller to complete operations such as paper feeding water needle cutting, opening and closing of the sizing beam and sizing roller, pressure and flow setting, and speed difference adjustment. The control panel provides an operating interface for operators, allowing them to manually set process parameters and simultaneously display the equipment operating status and various detection data in real time.

[0040] Example 1 When drawing paper before sizing on a high-speed cultural paper machine, the operating speed is generally 1600 m / min. After other conditions are met, the following operations are performed: 1. First, press the "Paper guiding water needle to paper guiding position" button on the control panel. After the two paper guiding water needles on the operating side and the transmission side have moved to the paper guiding position, press the "Paper guiding start" button to start the paper guiding water needle pump. The water needle cutting pressure is 300~600 bar. Paper guiding begins, and the width of the paper strip cut by the water needle is about 30~40cm.

[0041] 2. Then, start the paper feeding device and use the paper feeding rope included in the auxiliary paper feeding device to guide the paper strip to the front of the first drying cylinder of the post-drying. Then, according to the paper feeding program, the water needle position automatically enters the paper feeding position of the post-drying. The two paper feeding water needles move 20cm to the transmission side, and the paper strip automatically gets off the paper feeding rope. At this time, the post-drying paper feeding program starts, and each group of paper feeding blowers guides the paper strip to the front of the calender. The paper strip falls into the pulper.

[0042] 3. Press the "Close Upper and Lower Glue Rollers" button. After the feed flow rate reaches 1100L / min~1200L / min, set the metering bar pressure of the upper and lower glue rollers to 160kPa and the pressure zone pressure to 4kN / m. Then, press the "Close Upper and Lower Glue Rollers" button. After the upper and lower glue rollers close, some glue begins to be applied to the paper strip. The temperature and humidity of the paper strip increase instantly, and the tension decreases. Because the paper strip cannot be put into tension control at this time, the tension is controlled by the speed difference.

[0043] 4. Synchronously activate the speed difference compensation program to ensure that the speed difference compensation value when the upper and lower glue rollers complete closing reaches the preset value. This preset value is 4 times the speed difference between the glue roller drive speed and the first group of drive speeds in the rear drying section during operation. Specifically, using 70 / 80 gsm copy paper as a baseline, a 10 gsm basis weight change corresponds to ±0.5. The set value for double-sided offset paper is increased by 1 for each of these values, and this process continues for 10 seconds. Afterward, the speed difference compensation value automatically adjusts to the normal speed difference value ×2.

[0044] 5. Maintain this value until the full-width expansion step is initiated in the program. The paper guide needle on the drive side moves towards the drive side, and the paper guide needle on the operation side moves towards the operation side, expanding the paper strip to the full width. After the paper strip is expanded to the full width, the tension measuring device detects the paper tension. The tension value triggers the system program to switch to controlling the speed difference between the sizing roller and the post-drying section by the tension value. The paper strip speed difference compensation program stops synchronously.

[0045] 6. After completing the sizing process, adjust the tension of the paper guide strip and expand its width.

[0046] The above description is merely a specific embodiment of this application. Obviously, various modifications and combinations can be made without departing from the spirit and scope of this application. Accordingly, this specification and accompanying drawings are merely exemplary descriptions of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, the intent of this application includes these modifications and modifications. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the stated claims. It should also be noted that in the apparatus and method of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered equivalent solutions of this application. The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be applied within the widest scope consistent with the principles and novel features disclosed herein. The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although several exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A method for controlling the tension of paper strips on a paper feeding and closing roller, characterized in that, The method is applied to a papermaking system, which includes at least a paper feeding device, an auxiliary paper feeding device, a post-drying section, a sizing machine, a pulper, a monitoring system, a tension detection device, and a control system. The paper feeding device, the auxiliary paper feeding device, the post-drying section, the sizing machine, the pulper, the monitoring system, and the tension detection device are all electrically connected to the control system. The sizing machine has an upper sizing roller and a lower sizing roller. The method includes: The auxiliary paper feeding device guides the cut paper strips to the post-drying section and into the pulper; When the monitoring system detects that the cut paper strip to be glued falls into the pulper, it controls the upper and lower glue rollers of the gluer to close, and applies glue to the paper strip to be glued. At the same time, it gradually controls the speed difference between the upper and lower glue rollers and the post-drying section, so that the speed difference reaches a preset value when the upper and lower glue rollers are closed. After the paper feeding device expands the cut paper strip to its full width, the real-time tension detected by the tension detection device is obtained, and the speed difference between the upper and lower gluing rollers and the post-drying section is controlled based on the real-time tension.

2. The paper strip tension control method for the paper feed roller according to claim 1, characterized in that, The auxiliary paper feeding device includes a paper feeding rope and a blower plate electrically connected to the control system; the post-drying section includes multiple drying cylinders arranged along the paper web running direction; controlling the auxiliary paper feeding device to guide the cut paper strips to be sized to the post-drying section and fall into the pulper includes: The paper guide rope is controlled to pull the paper strip to be glued to the first set of drying cylinders along the paper web running direction in the multiple sets of drying cylinders, so that the paper strip to be glued moves along the multiple sets of drying cylinders to the last set of drying cylinders along the paper web running direction in the multiple sets of drying cylinders; When the paper strip to be glued reaches the last set of drying cylinders along the paper web running direction, the blowing plate is controlled to blow the paper strip to be glued into the pulper.

3. The paper strip tension control method for the paper feed roller according to claim 1, characterized in that, The paper guiding device includes a paper guiding water needle electrically connected to the control system. The control-assisted paper guiding device guides the cut paper strips to be glued to the front of the post-drying section. The method further includes: The paper-feeding needle is controlled to cut the paper web into strips to be glued.

4. The paper strip tension control method for the paper feed roller according to claim 3, characterized in that, The paper-feeding needles include drive-side paper-feeding needles and operating-side paper-feeding needles. The paper-feeding device expands the cut strip of paper to be glued to its full width, including: The paper guide needle on the drive side is controlled to move toward the drive side of the sizing machine, and the paper guide needle on the operating side is controlled to move toward the operating side of the sizing machine, so as to expand the cut paper strip to be sizing to the full width.

5. The paper strip tension control method for the paper feed roller according to claim 3, characterized in that, When the paper-feeding needle is used to cut the paper web, the cutting pressure is 300 bar to 600 bar.

6. The paper tension control method for the paper feed roller according to claim 3, characterized in that, The width of the paper strip to be glued is 30cm to 40cm.

7. The paper tension control method for the paper feed roller according to claim 2, characterized in that, The simultaneous and gradual control of the speed difference between the upper and lower glue application rollers and the subsequent drying section, so that the speed difference reaches a preset value when the glue application rollers are fully closed, includes: Control the speed difference between the upper and lower glue application rollers and the first set of drying cylinders in the rear drying section, so that the speed difference reaches a preset value when the upper and lower glue application rollers are closed. The preset value is four times the speed difference between the upper and lower glue rollers and the first set of drying cylinders in the rear drying section under normal operating conditions.

8. The paper tension control method for the paper feed roller according to claim 7, characterized in that, The basis weight of the paper strip to be glued is 70 g / m². 2 ~80g / m 2 When the basis weight of the paper strip to be glued changes by ±10 g / m 2 When the preset value is set, it is adjusted by ±0.5 times based on the 4 times.

9. The paper tension control method for the paper strip on the paper feeding and closing rollers according to any one of claims 2 to 8, characterized in that, The sizing machine further comprises an upper sizing beam and a lower sizing beam. The upper sizing beam is disposed on the paper feed side of the upper sizing roller, and the lower sizing beam is disposed on the paper feed side of the lower sizing roller. Metering bars are disposed on both the upper and lower sizing rollers. Before controlling the upper and lower sizing rollers of the sizing machine to close, the method further includes: Control the closure of the upper and lower glue application beams, and set the glue application pressure of the upper and lower glue application beams to 4KN / m; When the feeding flow rate of the upper and lower glue application beams reaches 1100L / min to 1200L / min, the pressure of the metering rods of the upper and lower glue application rollers is set to 160kPa to 170kPa.

10. The paper strip tension control method for the paper feed roller according to claim 9, characterized in that, After the speed difference reaches a preset value when the upper and lower glue application rollers have completed closing, the method further includes: After maintaining the preset value for 10 seconds, the speed difference is adjusted to twice the normal operating speed difference until the paper strip to be glued expands to the full width.

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