Online metering device for flexible strip and application of online metering device

Abstract

The invention discloses an online metering device for a flexible strip and application of the online metering device, and belongs to the field of industrial automatic metering. The device comprises an encoder measuring roller assembly and a measuring roller assembly, the encoder measuring roller assembly is used for metering and detecting the flexible strip; the encoder measuring roller assembly is provided with a measuring roller assembly used for preventing slipping errors and accumulation of the slipping errors. The measuring roller assembly is used for accurately measuring the flexible strip in real time; the measuring roller assembly comprises a first measuring roller and a plurality of measuring units, wherein the static friction coefficients of the contact surfaces of the measuring units are sequentially increased, and each measuring unit and the first measuring roller are in a running fit relationship. Under the action of the measuring roller assembly and the encoder measuring roller assembly, at least one unit with a high friction coefficient can be kept synchronous with a strip, so that a reliable internal reference signal is provided for a system and is used for identifying and compensating a slip error; the function of preventing slip errors and accumulation thereof from reducing the metering precision is achieved.

Description

Technical Field

[0001] This invention relates to the field of industrial automated metering, and in particular to an online metering device for flexible strip materials and its application. Background Technology

[0002] With the increasing demands for high-quality development in the tobacco industry, the consumption and analysis of various raw and auxiliary materials in the cigarette packaging process are becoming increasingly important. Among these, the M5-FX2 imported cigarette packaging unit, being an imported cigarette machine, suffers from several drawbacks. Its system is not open to external systems, and the M5 unit lacks statistics on cigarette paper usage. Furthermore, the statistical analysis and application of this data cannot accurately measure the usage of each unit and shift.

[0003] Currently, in the cigarette production process of the tobacco industry, the accurate metering of key flexible strip materials such as tipping paper and cigarette paper is crucial for achieving cost control, quality assurance, and refined production management. At present, the industry generally uses contact measurement methods for online metering of these materials. The core device typically consists of an encoder-measuring roller assembly, which comprises a rotary encoder and a mechanical component called a measuring roller. Its working principle is: relying on the static friction between the flexible strip and the surface of the measuring roller, the measuring roller rotates. The encoder detects the rotation angle or speed of the measuring roller and indirectly calculates the material's travel length and speed. This technology has become the industry mainstream due to its relatively simple structure and low cost.

[0004] However, this contact-based metering method, which relies on friction transmission, has an inherent and difficult-to-eradicate technical flaw: the error caused by slippage and its accumulation. Once slippage occurs, the data measured by the encoder is no longer the true displacement of the material, but rather distorted information about the roller motion containing errors. More seriously, this error continues to accumulate during the production process, leading to a series of specific problems: 1. Severely Distorted Material Consumption Measurement: The system displays increasingly larger discrepancies between the consumption amount and the actual material usage. This directly leads to inaccurate production cost accounting, masking material waste and hindering true lean cost management. 2. Blind Spots in Quality and Process Control: The accuracy of related process controls (such as punching positioning, printing registration, and filter tip length control) based on distorted length or speed signals decreases, affecting the consistency of product appearance and internal quality. 3. Unplanned Downtime and Efficiency Loss: Errors caused by slippage and their accumulation make it impossible to accurately predict the remaining amount of roll material. Automatic roll changing or early warning functions relying on distorted measurement data may fail, easily causing unplanned production interruptions due to material depletion. This is the serious consequence of late roll changing. Furthermore, premature roll changing to avoid late changes results in wasted material, directly impacting the overall equipment efficiency (OEE).

[0005] In response to the aforementioned problems of slippage leading to errors and error accumulation, this invention designs an online metering device for flexible strips and its application. Summary of the Invention

[0006] The purpose of this invention is to provide an online metering device for flexible strip materials and its application. Through the function of the measuring roller assembly and the encoder measuring roller assembly, it can prevent slippage errors and their accumulation from reducing the metering accuracy; it can solve the problems of errors caused by slippage and their accumulation mentioned above.

[0007] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: This invention relates to an online metering device for flexible strip materials, comprising an encoder measuring roller assembly and a measuring roller assembly; the encoder measuring roller assembly is equipped with a measuring roller assembly to prevent slippage errors and their accumulation; the measuring roller assembly performs real-time accurate metering and detection of the flexible strip material. This configuration constitutes the basic framework of the device, wherein the measuring roller assembly is the core functional module for solving the slippage problem.

[0008] In a preferred embodiment of the present invention, the measuring roller assembly includes at least one first measuring roller and at least one measuring unit whose static friction coefficient increases sequentially and is higher than that of the first measuring roller. Each measuring unit and the first measuring roller are in a rotational fit relationship. The overall circumferential surfaces of the first measuring roller and the measuring units in the measuring roller assembly are coplanar and without any step difference. The measuring units utilize their higher static friction than the first measuring roller to ensure that when the first measuring roller slips, at least one measuring unit does not slip, thus guaranteeing measurement accuracy and preventing slippage errors and their accumulation. This design introduces redundant measuring units with different friction coefficients, utilizing tribological principles to ensure that under any slippage condition, at least one unit with a high friction coefficient remains synchronized with the strip, thereby providing a reliable internal reference signal for the system to identify and compensate for slippage errors.

[0009] In a preferred embodiment of the present invention, each measuring unit and the first measuring roller are respectively fixedly connected to an encoder input shaft, and each encoder input shaft is sequentially configured as a hollow shaft with a central through hole and an increasing inner diameter, and each measuring unit is sequentially configured as a hollow structure with a central through hole and an increasing inner diameter; each hollow shaft is fixedly connected to a grating disk; each grating disk corresponds to an independent photoelectric read head for collecting photoelectric signals; each photoelectric read head is electrically connected to a controller in the encoder measuring roller assembly; each photoelectric read head is equipped with an independent optical isolation structure, or the hollow shaft is rotatably fitted with an optical isolation ring between each two adjacent photoelectric read heads; the measuring roller assembly is sequentially installed with the first measuring roller and multiple measuring units from the outside to the inside. This structure configures an independent, high-precision photoelectric encoder sensor chain for each measuring unit, ensuring accurate measurement of the independent rotational speed of each unit. The nested design of the hollow shafts achieves a compact structure. The optical isolation structure or optical isolation ring effectively prevents crosstalk between the optical paths of each encoder, ensuring the independence and accuracy of each rotational speed signal.

[0010] In a preferred embodiment of the present invention, the measuring unit employs a second measuring roller; and the friction coefficient of each of the second measuring rollers increases sequentially; they are respectively a low-friction roller, a medium-friction roller, a medium-high-friction roller, and a main reference roller; the surfaces of the low-friction roller, the medium-friction roller, the medium-high-friction roller, and the main reference roller are respectively made of hard anodized aluminum, wear-resistant nylon, hard polyurethane, and soft microporous polyurethane. This material scheme provides a gradient path for the friction coefficient; from the low-friction metal roller to the high-friction elastomer roller, a clear slippage sequence is formed; the soft microporous polyurethane is designated as the main reference roller with the highest friction coefficient, with the aim of utilizing its excellent surface adhesion and elastic deformation ability to maximize the static friction with the strip, ensuring that it does not slip under most operating conditions, thus serving as the most reliable internal reference of the system.

[0011] As a preferred embodiment of the present invention, it further includes a mounting plate; an encoder measuring roller assembly and a laser length measuring instrument are fixedly mounted on the mounting plate. The purpose of adding the laser length measuring instrument is to provide a non-contact external high-precision measurement benchmark for periodically calibrating or comparing the output of the contact encoder measuring roller assembly in real time, thereby further eliminating possible residual errors in the system and verifying and improving the reliability of the redundant measurement results of the multi-friction rollers.

[0012] As a preferred embodiment of the present invention, the laser length measuring instrument is further equipped with a laser sleeve; an air dust collector is also fixedly installed at the port of the laser sleeve; the air dust collector removes dust from the air around the port of the laser sleeve to ensure that the air around the port of the laser sleeve remains clean. The function of this air dust collector is to actively remove dust from the air near the window, preventing dust from adhering to the optical lens or suspending in the optical path and interfering with the measurement. This is a key protective measure to maintain the long-term stable operation and high measurement accuracy of the laser length measuring instrument in industrial dusty environments.

[0013] In a preferred embodiment of the present invention, the laser sleeve is fixedly connected to the purification outlet of an air dust collector. Purified air discharged through the purification outlet of the air dust collector exits from the inside of the laser sleeve to the outside, preventing external dust from entering the laser sleeve and thus avoiding dust interference and reduced accuracy. This design forms a positive pressure clean air curtain, continuously introducing clean air into the laser sleeve and allowing it to flow outwards from the port. This creates a positive airflow barrier at the port, effectively preventing dust from the external environment from flowing back into the laser sleeve and contaminating the optical components, achieving dynamic and higher-level dust protection.

[0014] As a preferred technical solution of the present invention, the laser length measuring instrument adopts a laser Doppler velocimeter; the laser Doppler velocimeter is selected because it directly and non-contactly measures the surface velocity of an object based on the Doppler effect, with extremely high accuracy and no wear, and the length information can be obtained by integrating the velocity, making it an ideal choice as an external calibration benchmark.

[0015] As a preferred embodiment of the present invention, the online metering device can also be applied to the metering and testing of tipping paper and cigarette paper used in tobacco production. This clarifies the most direct and important application area of ​​the present invention: solving the problem of accurate metering of high-value auxiliary materials in tobacco industrial production.

[0016] The present invention has the following beneficial effects: 1. This invention uses a design that forms the basic framework of a measuring roller assembly and an encoder measuring roller assembly. It introduces redundant measuring units with different coefficients of friction and uses the principle of tribology to ensure that at least one unit with a high coefficient of friction can keep synchronized with the strip under any slippage condition. This provides a reliable internal reference signal for the system to identify and compensate for slippage errors, thereby preventing slippage errors and their accumulation from reducing measurement accuracy.

[0017] 2. The present invention features a design in which the measuring roller assembly is installed sequentially from the outside to the inside, consisting of a first measuring roller and multiple measuring units. This design ensures accurate measurement of the independent rotational speed of each unit, achieves a compact structure through the nested design of its hollow shafts, and effectively prevents crosstalk between the optical paths of each encoder by using an optical isolation structure or optical isolation ring, thus guaranteeing the independence and accuracy of each rotational speed signal.

[0018] 3. This invention ensures uniform contact between the measuring unit and the first measuring roller by coaxially mounting the measuring unit and ensuring that the outer cylindrical surfaces of all rollers are strictly coplanar and have no height difference. Simultaneously, the static friction coefficients of the surfaces are designed to increase sequentially, forming a friction coefficient gradient. When slippage occurs due to deteriorating working conditions, the roller with the lowest friction coefficient will lose its step first, while the main reference roller with the highest friction coefficient should lose its step last or even never lose its step, thus guaranteeing at least one reliable speed reference signal. This invention offers the advantages of ensuring the most reliable speed reference signal from the main reference roller and guaranteeing measurement accuracy. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of an online metering device for flexible strip provided by the present invention in Embodiment 1; Figure 2 This is a schematic diagram of the measuring roller assembly provided by the present invention in Embodiment 1; Figure 3 This is an exploded view of the measuring roller assembly provided by the present invention in Embodiment 1; Figure 4 This is a structural perspective view of an online metering device for flexible strip provided by the present invention in Embodiment 1; Figure 5 This is a schematic diagram of the structure of an online metering device for flexible strip provided by the present invention in Embodiment 2.

[0020] Explanation of reference numerals in the attached figures: 1-Flexible strip, 2-Encoder measuring roller assembly, 3-Measuring roller assembly, 4-Mounting plate, 5-Laser length measuring instrument, 301-First measuring roller, 302-Measuring unit, 303-Hollow shaft, 304-Raster disk, 305-Photoelectric reading head, 306-Optical isolation ring. Detailed Implementation

[0021] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0022] Example 1

[0023] like Figures 1 to 4As shown in the figure, an online metering device for flexible strip material provided by an embodiment of the present invention includes an encoder measuring roller assembly 2 and a measuring roller assembly 3. In this embodiment, the flexible strip material 1 specifically refers to tobacco paper or cigarette paper. The encoder measuring roller assembly 2 is responsible for the core metering function, and it integrates the measuring roller assembly 3 and the subsequent processing controller.

[0024] Measuring roller assembly 3 is the core component for preventing slippage. For example... Figure 2 As shown, it includes a first measuring roller 301 and three measuring units 302 installed sequentially. Each measuring unit 302 is a second measuring roller with a hollow structure having a central through hole and an increasing inner diameter. These measuring units 302 are coaxially mounted with the first measuring roller 301, and the outer cylindrical surfaces of all rollers are strictly coplanar with no height difference to ensure uniform contact with the flexible strip 1. Each measuring unit 302 is rotatably coupled to the first measuring roller 301, allowing it to rotate independently. Crucially, the static friction coefficients of the contact surfaces between the first measuring roller 301 and the three measuring units 302 and the strip are designed to increase sequentially from the first measuring roller 301 towards the other end. This sequential increase aims to minimize the impact on adjacent measuring units 302 when slippage occurs due to the relatively small difference in static friction coefficients. The first measuring roller 301 can be made of conventional materials such as chrome-plated steel, while the three measuring units 302 are made of hard anodized aluminum, hard polyurethane, and soft microporous polyurethane in sequence, forming a gradient of friction coefficients. The purpose of this gradient friction design is to create a "slippage sequence": when the working conditions deteriorate and slippage occurs, the roller with the lowest friction coefficient will lose synchronization first, while the "main reference roller" with the highest friction coefficient should lose synchronization last or even never lose synchronization, thereby ensuring at least a reliable speed reference signal.

[0025] Meanwhile, the reason why the measuring roller assembly 3 here does not use the "main reference roller" with the highest coefficient of friction is that its coefficient of friction is the highest. It will cause excessive friction on the flexible strip 1 such as tipping paper or cigarette paper, which may not only scratch or wear the printing layer, but also significantly increase the tension difference (ΔT) between its inlet and outlet sides, that is, disrupt the tension balance and may cause paper shaking. Therefore, the static friction coefficient of the first measuring roller 301 will adopt the "optimal value" designed for stability, controllability and matching the overall system, and the axial length ratio of the surface of the first measuring roller 301 will be the largest. The proportion of the measuring unit 302 in the axial length direction will be as small as possible to reduce its wear on the flexible strip 1 and reduce tension imbalance.

[0026] The optimal design layout is as follows: the measuring roller assembly 3 includes two first measuring rollers 301 and one measuring unit 302; the measuring unit 302 with a higher static friction coefficient is sandwiched in the middle by the two first measuring rollers 301 with "optimal value" static friction coefficient, that is, the two first measuring rollers 301 are symmetrically distributed on both sides of the measuring unit 302; thereby improving the tension balance of the flexible strip 1 when it passes through the measuring roller assembly 3, and also has the advantages of being less prone to deviation during measurement and detection and minimizing the impact of wear.

[0027] To accurately capture the independent rotational speed of each roller, such as Figures 2-3 As shown, each measuring unit 302 and the first measuring roller 301 are connected to an independent encoder sensing unit. Specifically, each roller is fixedly connected to a hollow shaft 303, the inner diameters of which increase sequentially, forming a nested relationship to save space; and each pair of adjacent hollow shafts 303 are rotated together by bearings. A grating disk 304 is fixed to the end of each hollow shaft 303, and the larger the inner diameter of the hollow shaft 303, the shorter its shaft length, to ensure that the end of the hollow shaft 303 with the smallest inner diameter has sufficient length to accommodate the lengths of the other hollow shafts 303 and the space required to install the grating disk 304. Corresponding to each grating disk 304, an independent photoelectric read head 305 is provided, which contains an LED light source and a photodetector, and is encapsulated with existing optical isolation structures (such as filters and sealed cavities). The photoelectric read head 305 converts the detected grating disk rotation signal into electrical pulses and sends them to the controller. Optical isolation rings 306 are fitted on the hollow shafts 303 between adjacent photoelectric read heads 305. Nested hollow shafts enable a compact multi-axis structure; independent grating disks and photoelectric read heads ensure independent acquisition of signals from each channel; optical isolation structures or optical isolation rings effectively prevent cross-interference between the optical paths of multiple encoders, ensuring the purity and accuracy of each speed signal.

[0028] Example 2

[0029] A more preferred technical solution based on Embodiment 1 is as follows: Figure 5As shown, when data acquisition and equipment debugging are required for the online metering device in Embodiment 1, an external high-precision reference with no risk of slippage must be introduced before the online metering device leaves the factory. This reference is used to calibrate and verify the online metering device and to determine whether it meets the factory standards. Therefore, a laser length measuring instrument 5 and its mounting plate 4 are added. The encoder measuring roller assembly 2 and a laser Doppler velocimeter are simultaneously fixedly mounted on the mounting plate 4 as the laser length measuring instrument 5. The emitting end of the laser length measuring instrument 5 is equipped with a laser sleeve 501, and an air dust collector 502 is integrated at the sleeve port. The air dust collector 502 continuously generates clean air, and a portion of the clean air is introduced into the laser sleeve 501 through the connecting air pipe 503, forming a positive pressure airflow that is discharged from the inside out. Compared with the static sealing method, this embodiment has the advantages of reducing component costs by not requiring extremely high sealing technology and facilitating heat dissipation. At the same time, the air dust collector 502 needs to meet the requirements of use under harsh working conditions such as dust and oil mist, and the dust removal effect requirements are extremely high. The design of the 502 air dust collector and positive pressure air curtain is specifically designed to combat dust in industrial environments such as tobacco. Through active cleaning and gas barriers, it ensures that the laser beam path is not contaminated, thereby maintaining the ultra-high accuracy and stability of laser measurement over a long period of time.

[0030] Working Principle: In this embodiment, the online metering device operates by having the flexible strip 1 (such as tipping paper) move in close contact with the surface of the measuring roller assembly 3, relying on friction to drive the rotation of each roller. The controller reads the encoder pulse signals corresponding to the first measuring roller 301 and each measuring unit 302 in real time and calculates their respective rotational speeds. In an ideal, slip-free state, all rotational speeds should be consistent. If a difference in rotational speed is detected, it indicates that slippage has occurred. In the system algorithm of the encoder measuring roller assembly 2 (for example, the signal with the highest and most stable rotational speed is regarded as the reference closest to the actual strip speed; the reason is that the rotational power of the first measuring roller and all measuring units comes solely from the static friction between the moving flexible strip such as tipping paper and the roller surface), it can immediately identify which rollers have slipped and automatically switch or merge the signals from the non-slipping rollers as valid measurement values, thereby avoiding the inclusion of slippage errors in the total length. At the same time, the laser length measuring instrument 5 continuously provides a non-contact reference length signal, which can be periodically compared with the output of the encoder assembly 2 for system calibration, accuracy verification, or as a higher-level fusion data source.

[0031] This invention employs a dual-protection mechanism combining internal multi-friction coefficient redundant measurement with external non-contact reference correction. While maintaining compatibility with existing contact measurement systems, it fundamentally solves the problem of detecting and preventing slippage errors. It is particularly suitable for the production process of flexible strip materials such as tobacco paper and cigarette paper, which have extremely high requirements for metrological accuracy and reliability.

[0032] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.

Claims

1. An online metering device for flexible strip, comprising an encoder measuring roller assembly (2), characterized in that, It also includes a measuring roller assembly (3); The encoder measuring roller assembly (2) is provided with a measuring roller assembly (3) for preventing slippage error and its accumulation; the measuring roller assembly (3) performs real-time accurate measurement and detection on the flexible strip (1).

2. The online metering device for flexible strip as described in claim 1, characterized in that, The measuring roller assembly (3) includes at least one first measuring roller (301) and at least one measuring unit (302) whose contact surface has a static friction coefficient that increases sequentially and is higher than that of the first measuring roller (301). Each measuring unit (302) and the first measuring roller (301) are in a rotational fit relationship. The overall circumferential surfaces of the first measuring roller (301) and the measuring unit (302) in the measuring roller assembly (3) are coplanar and have no step difference. The measuring unit (302) utilizes its static friction force to be higher than that of the first measuring roller (301) so that when the first measuring roller (301) slips, at least one of the measuring units (302) does not slip, thereby ensuring measurement accuracy and preventing slippage error and preventing the accumulation of slippage error.

3. The online metering device for flexible strip as described in claim 2, characterized in that, Each of the measuring units (302) and the first measuring roller (301) is fixedly connected to an encoder input shaft, and each encoder input shaft is sequentially configured as a hollow shaft (303) with a through hole in the center and an increasing inner diameter, and each measuring unit (302) is sequentially configured as a hollow structure with a through hole in the center and an increasing inner diameter; each hollow shaft (303) is fixedly connected to a grating disk (304); each grating disk (304) is corresponding to an independent photoelectric reading head (305) for collecting photoelectric signals; each photoelectric reading head (305) is electrically connected to the controller in the encoder measuring roller assembly (2); each photoelectric reading head (305) is equipped with an independent optical isolation structure or the hollow shaft (303) is rotatably fitted with an optical isolation ring (306) between each two adjacent photoelectric reading heads (305).

4. The online metering device for flexible strip as described in claim 3, characterized in that, The measuring roller assembly (3) is arranged from the outside to the inside as follows: a first measuring roller (301) and multiple measuring units (302) with increasing friction coefficients are installed sequentially.

5. An online metering device for flexible strip as described in claim 3, characterized in that, The measuring unit (302) uses a second measuring roller; and the friction coefficient of each second measuring roller surface increases sequentially; they are respectively a low-friction roller, a medium-friction roller, a medium-high-friction roller, and a main reference roller; the surfaces of the low-friction roller, the medium-friction roller, the medium-high-friction roller, and the main reference roller are respectively made of hard anodized aluminum, wear-resistant nylon, hard polyurethane, and soft microporous polyurethane.

6. The online metering device for flexible strip as described in claim 1, further comprising a mounting plate (4); characterized in that, The encoder measuring roller assembly (2) and the laser length measuring instrument (5) are fixedly installed on the mounting plate (4).

7. An online metering device for flexible strip as described in claim 6, characterized in that, The laser length measuring instrument (5) is also equipped with a laser sleeve (501); an air dust collector (502) is also fixedly installed at the port of the laser sleeve (501).

8. An online metering device for flexible strip as described in claim 7, characterized in that, The laser sleeve (501) is fixedly connected to the purification outlet of the air dust collector (502).

9. The online metering device for flexible strip and its application as described in claim 7, characterized in that, The laser length measuring instrument (5) adopts a laser Doppler velocimeter.

10. The application of the online metering device for flexible strip as described in any one of claims 1-9, characterized in that, The online metering device is used for the metering and testing of tipping paper and cigarette paper used in tobacco production.

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