SURVEILLANCE TECHNOLOGY FOR NONWOVEN FABRIC PLANTS

Description

[0001] The invention relates to a monitoring technology for nonwoven fabric production plants.

[0002] Nonwovens made from various fiber types and fiber mixtures are used in a wide variety of areas (e.g. hygiene products, automotive trim, packaging or building materials).

[0003] Synthetic fibers are the preferred starting material. Recycled fibers, e.g., from plastic or carbon materials, are also now processed into nonwovens.

[0004] The production of nonwovens, i.e., finished nonwoven products, generally takes place in several steps. First, fibers are extracted and processed, usually from compressed bales, in fiber preparation equipment. Different fiber types may be blended to create a fiber mixture. From the processed fibers, a relatively loose fiber nap, a so-called nonwoven pre-product, is formed. This is achieved using nap formation equipment, particularly mechanical or aerodynamic cards or carding machines. This nonwoven pre-product does not yet possess the desired structure, especially thickness or strength, of the finished nonwoven. To produce the finished nonwoven, the nonwoven pre-product is processed in further steps. During this further processing, for example in a lay-up machine or a needling machine, the structure of the previously formed fiber nap is modified.Depending on the application, the nonwoven pre-product is processed into the finished nonwoven fabric in a varying number of processing steps and methods.

[0005] In practice, nonwoven fabric production plants are known where measurements are carried out on the finished nonwoven fabric at the end of the production plant or behind a consolidation machine.

[0006] The prior art also includes the documents WO 2011 / 110145 A1, WO 2017 / 117688 A1, EP 0 189 985 A1, DE 40 38 684 A1, EP 1 316 630 A1, EP 2 660 375 A2, DE 199 43 079 A1, EP 0 303 345 A2, and EP 0 485 881 A1. These documents disclose, for example, the measurement of a nonwoven fabric behind a carding machine or a cross-layer to correct a weight measurement on a belt scale. Measurements on a nonwoven fabric are also used to control a carding machine. From the field of

[0007] In spinning preparation, methods for measuring material processed into yarn are also known. EP 0 604 874 discloses a technique for controlling the microenvironmental conditions in a test zone or a process for producing cotton yarns.

[0008] The object of the present invention is to provide an improved monitoring technology for

[0009] The invention aims to demonstrate nonwoven fabric production facilities. It solves this problem with the features of the independent claims.

[0010] The disclosure includes a monitoring technology comprising both a monitoring method and suitable devices. In particular, the disclosure includes a nonwoven pre-production plant and a monitoring device.

[0011] The combinations of known processing steps and machines are highly diverse. The disclosed monitoring technology is particularly suitable for use in various plant configurations. Depending on the application, specific requirements are placed on the quality of the finished nonwoven product. These requirements can relate to the thickness, composition, structure, feel, color, or load-bearing capacity of the nonwoven product.

[0012] Throughout the multi-stage manufacturing process of a nonwoven product, there are numerous settings and process parameters that influence the quality of the final product. It is particularly advantageous to automate machine settings, especially in the early stages of production. These settings can be adjusted once at the start of a production run (setup time) and / or continuously during production.

[0013] The nonwoven pre-production plant can be part of a larger nonwoven manufacturing plant. The nonwoven pre-production plant processes fibers into a nonwoven semi-finished product. It represents the first process stage within the larger nonwoven manufacturing plant. A nonwoven pre-production plant can, in particular, include one or more fiber preparation units and one or more pile formation units, such as a carding machine. The entire nonwoven manufacturing plant processes fibers into the finished nonwoven fabric. The nonwoven semi-finished product is an intermediate product in the overall nonwoven manufacturing process.

[0014] The monitoring device can be part of a nonwoven pre-production plant. In subsequent processing machines, the nonwoven pre-product is further processed into a nonwoven fabric.

[0015] A first essential aspect of the invention relates to the detection of properties of an unprocessed nonwoven pre-product.

[0016] In the nonwoven fabric pre-production plant, an unprocessed fiber pile, the nonwoven fabric pre-product, is manufactured. This first process step is also called pile formation or "web formation." The production of the nonwoven fabric pre-product, i.e., the unprocessed pile, can also take place in several steps. For example, the nonwoven fabric pre-product can be produced in several carding machines in succession to achieve the necessary pile thickness for further processing.

[0017] The unprocessed pile of the nonwoven pre-product exhibits little cohesion between the fibers. The nonwoven pre-product remains unprocessed, particularly after pile formation (e.g., since exiting a carding machine). The fiber pile (nonwoven pre-product) formed in the pile-forming unit is unchanged within the collection area. Any alteration to the structure of the nonwoven pre-product (e.g., through bundling, consolidation, or laying) only occurs downstream of the collection area.

[0018] The nonwoven pre-product is typically modified in its structure after being processed in a nonwoven pre-production line. This processing includes, for example, bonding the pile. Various mechanical, thermal, and chemical bonding techniques are used in practice. For instance, the pile is calendered, needle-punched, or bonded with water jets during processing. The pile structure is modified (e.g., bonded) to achieve the desired product properties of the nonwoven.

[0019] One aspect of the present invention is that the properties of a nonwoven pre-product are automatically recorded in order to monitor the production process. The recorded properties of the nonwoven pre-product can include, for example, the basis weight, moisture content, fiber orientation, fiber openness, fiber blend ratio, temperature, density, and / or the electrical or electrostatic charge of the fiber pile. Both multiple properties and a specific selection of properties can be recorded by measurement.

[0020] Recording the properties of the nonwoven precursor offers several advantages. These properties significantly influence processing in the downstream converting equipment of the nonwoven manufacturing plant. For example, the degree of fiber openness in the nonwoven precursor can affect subsequent bonding. Fiber orientation in the nonwoven precursor affects the mechanical strength of the finished nonwoven product. Therefore, recording the properties of the nonwoven precursor is advantageous. In particular, recording the properties of the nonwoven precursor is beneficial for optimizing the quality of the finished nonwoven fabric. Recording the properties of the nonwoven precursor is also advantageous for optimizing the downstream converting equipment of the nonwoven manufacturing plant.

[0021] It remains advantageous to determine the properties of the nonwoven precursor before further processing. Certain properties are more difficult to measure after processing. In particular, certain measurement methods, such as measurements using infrared or radioactive radiation, can be especially well applied to the thin fiber nap of the nonwoven precursor. For example, the transmission of radiation through a thin fiber nap can be measured more accurately than through a processed nonwoven. Measurements using infrared and / or radioactive radiation on the nonwoven precursor are particularly advantageous.

[0022] Another essential aspect of the disclosure is the recording of a property of the nonwoven pre-product across its width. The nonwoven pre-product is conveyed as a web-like fiber layup in the production direction. The spatial or areal distribution of the properties lengthwise and / or crosswise to the production direction is of particular importance for the quality of the product. Properties such as basis weight, fiber openness, or fiber orientation can exhibit local variations. Local defects, material accumulations, clumps, or similar effects can be recorded in the spatial or areal distribution of the properties.

[0023] The properties are preferably captured across the entire width of the nonwoven pre-product. Width, as used in this disclosure, means the extent of a fiber stream or a nonwoven pre-product (i.e., a pile web) transverse to the production direction (i.e., conveying direction). Preferably, the capture area extends across the entire working width of a pile-forming device (e.g., a carding machine).

[0024] The data can be acquired using a stationary or movable sensor. Acquisition is preferably performed with constant accuracy across the entire width of the nonwoven fabric precursor. Advantageously, an (approximately) continuous distribution of the properties is captured. In this way, a cross-sectional profile and / or a longitudinal distribution of the properties can be determined.

[0025] In particular, consecutive measurements can be taken at multiple local acquisition points. These local acquisition points can be offset from each other longitudinally and / or transversely. Preferably, the local acquisition points overlap. A continuous property profile can be generated, in particular, from a combination of overlapping acquisition points with constant measurement accuracy. Preferably, location information and / or time information is recorded for each acquired property.

[0026] Preferably, the two-dimensional distribution of a property is recorded. Preferably, the weight is recorded as an area weight distribution. The spatial distribution of a property preferably refers to the area of ​​the pile. Spatial distribution preferably refers to the areal distribution of a property parallel to the pile. It is particularly advantageous for economical measurement technology not to record a third dimension of a property distribution, especially perpendicular to the pile. Measurement inaccuracies in the distribution perpendicular to the area of ​​the pile can lead to significant distortions or noise in the measurement result.

[0027] The properties of the nonwoven precursor are crucial for the production of a high-quality nonwoven fabric. If the properties of the resulting fiber pile deviate from the desired characteristics, this can lead to production problems during further processing of the nonwoven precursor or to a reduction in the quality of the final product. For example, the moisture content in the nonwoven precursor can affect its performance in certain machines. It is therefore advantageous to assess the properties of the fiber pile before initial processing, especially if the pile structure is altered during this process. Structural changes occur particularly during the bonding of the pile.

[0028] Higher quality requirements can be met through automated adjustments to regulate or control the properties of the nonwoven pre-product.

[0029] In practice, the properties of the nonwoven product are only checked, if at all, at the end of the production process. Adjustments to optimize the quality of the nonwoven product are usually made manually by the machine operator and depend heavily on the individual's experience and qualifications. Furthermore, these adjustments are often only made at the start of a production run. Automated monitoring ensures product quality regardless of the operator.

[0030] Another advantage of recording the properties of the nonwoven pre-product lies in using the recording results for automated adjustment of the nonwoven pre-production line. The recorded properties can be used for a one-time adjustment during a changeover or production start-up. Furthermore, the properties can be controlled during production operation by adjusting the nonwoven pre-production line based on the recorded results. Controlling a fiber preparation unit and / or a pile formation unit based on the recorded properties of the nonwoven pre-product is particularly advantageous. Recording the properties close to the exit of the nonwoven pre-product from a pile formation unit is especially beneficial for this purpose.

[0031] The earlier in the production process the properties of the nonwoven pre-product are recorded, the shorter the dead times that can be achieved in machine control. Short dead times improve control accuracy. Early detection of property deviations reduces scrap. Recording the properties of the unprocessed nonwoven pre-product allows for particularly tighter quality tolerances in the finished nonwoven product.

[0032] Non-contact measurement techniques, such as infrared, X-ray, or radioactive radiation, as well as optical measurement methods, can be used to determine the properties of the nonwoven pre-product. One or more sensors or radiation sources can be positioned above and / or below the fiber pile. The sensors can be stationary or movable. A combination of stationary and movable sensors is also possible. In particular, sensors can be moved across the width of the nonwoven pre-product perpendicular to the production direction. This is especially advantageous for capturing a spatial or planar distribution of the properties.

[0033] A sensor bar can also be used that extends across the width of the nonwoven fabric pre-product.

[0034] The measurements take place within a detection area whose location within the production plant is particularly advantageous. Measurements can be performed locally and / or globally on the nonwoven pre-product. In particular, sensors, e.g., for moisture detection, can perform local measurements. Furthermore, sensors can perform measurements over a specific area of ​​the nonwoven pre-product.

[0035] The detection area for recording the properties of the nonwoven pre-product is preferably located directly at or near the point where the nonwoven pre-product exits the pile formation unit. This arrangement is advantageous because the property data is recorded with the shortest possible time lag compared to the pile formation process. Particularly for controlling a fiber preparation or pile formation process based on the recorded properties, shorter dead times can be achieved by positioning the detection area close to the pile formation unit. Shorter pile formation cycle times between the pile formation process and the property measurement can improve control accuracy in the case of a control system. Material waste can also be reduced.

[0036] Furthermore, it is advantageous to measure the properties of the fiber pile before it is processed in a subsequent process step, thereby altering its structure. Positioning the measurement area in the production direction upstream of a downstream processing unit, preferably upstream of a first lay-up unit or a first bonding unit, is particularly advantageous. Certain properties of the nonwoven pre-product, such as fiber orientation or fiber openness, can be more accurately measured in the unprocessed fiber pile. The properties of the nonwoven pre-product to be measured can also be modified during downstream processing. This advantageous arrangement of the measurement area facilitates the correlation of property deviations with potential causes in the fiber preparation or pile formation process.

[0037] The monitoring procedure serves to oversee the production process and product quality. Depending on the application, high quality requirements may be placed on the nonwoven fabric. As part of quality assurance, manufacturers of nonwoven fabrics have an interest in monitoring the production process. It is particularly advantageous to store and document the recorded properties of the nonwoven pre-product. This allows for better identification of the causes of quality deviations in the nonwoven fabric.

[0038] One embodiment of the monitoring method is particularly advantageous for the automated adjustment of the nonwoven pre-production plant.

[0039] The monitoring device can be part of a nonwoven pre-production plant specifically designed to carry out the monitoring process. Implementing the monitoring device in a production plant with a central control system is particularly advantageous. The monitoring device can include specially designed actuators for setting and / or controlling the nonwoven pre-production plant. These actuators can have actuators that allow for the implementation of physical settings on a fiber preparation unit or a pile formation unit.

[0040] Another essential aspect of the disclosure is the monitoring of the moisture and / or electrostatic charge of the fibers or the nonwoven precursor. This aspect of the disclosure has its own inventive significance.

[0041] The disclosed monitoring technology ensures that changing environmental conditions or fluctuating fiber properties do not negatively affect product quality. Quality deviations can be prevented or mitigated. This monitoring technology also reduces rejects.

[0042] Friction can cause materials or components to become electrostatically charged. In the nonwovens industry, fiber shedding or fiber adhesion to components due to electrostatic fields can be undesirable.

[0043] Electrically charged fibers can easily attach to machine components, e.g. Conveyor belts, adhere to them and disrupt the production process. This is especially true for materials that are not electrically conductive or only weakly conductive (e.g., . (Plastics) can lead to electrostatic charging of the fiber material.

[0044] Monitoring the electrical charge can prevent electrical breakdowns that cause sparking.

[0045] The generation of electrostatic fields is closely linked to the moisture content of the fiber material and the surrounding air. Above a certain moisture level, electrical charges in the fiber material can be reduced or even prevented. Both the moisture content of the fibers themselves and of the surrounding air play a role in the quality of the manufacturing process.

[0046] In addition to electrostatic effects, moisture can also have a negative impact on machine components. For example, excessive moisture can lead to corrosion of machine components. Excessive fiber moisture can also result in undesirable properties in the nonwoven precursor or finished nonwoven product (e.g., . Clumping). Insufficient humidity can promote electrostatic fields.

[0047] Therefore, monitoring the moisture content and / or electrical charge of the fibers and / or the nonwoven precursor is advantageous for product quality and system durability. Ideally, the moisture content is maintained within an optimal range. Preferably, the relative humidity is considered in relation to the ambient temperature.

[0048] The climatic conditions of a facility can vary considerably depending on its location and the time of year. Seasonal, climatic, and weather-related variations in environmental conditions at the production site can be mitigated by monitoring technology. Humidity and ambient temperature can be controlled independently of external environmental conditions. Unwanted fiber shedding or fiber adhesion can be prevented worldwide.

[0049] Especially with fiber blends from different fiber types and sources, the properties of multiple fiber streams can be monitored separately. Fibers are often delivered as compressed bales. Depending on storage and transport conditions, the fibers introduced into the system can exhibit different properties (e.g., moisture content). Automated monitoring of the fiber or nonwoven precursor properties can compensate for external influencing factors.

[0050] The moisture content and / or electrical charge of the fibers or a nonwoven precursor are detected by a sensing device. The sensing device can comprise one or more sensors. Infrared sensors are preferably used. The sensing device is arranged in the nonwoven fabric production plant such that the properties are detected within a suitable detection range.

[0051] For automated monitoring, the data acquisition results are processed in an electronic data processing unit. These results represent an important data source. In the context of digitized production (Industry 4.0), the data acquisition results can be analyzed for various purposes. For example, the data can be used for the regulation or control of the plant. Alternatively or additionally, the data acquisition results can be used for process documentation and quality assurance. The data can be processed in real time and / or stored permanently.

[0052] Based on the detected humidity or electrical charge, appropriate adjustments can be made to the system automatically. A positioning instruction is generated for an actuator of the system, machine, or component. This positioning instruction is an electronic signal. It can be exchanged, in particular, via a bus system between data processing units (e.g., the detection device and a system controller).

[0053] Advantageously, the ambient conditions in a specific climate-controlled area of ​​the nonwoven fabric production plant can be adjusted using an air conditioning system. The air conditioning system is preferably designed to heat or cool the ambient air. In addition, the air can be humidified and / or dehumidified. Advantageously, moisture can be applied directly to the fiber material (e.g., by spraying, brushing, or wetting). Alternatively or additionally, moisture can be increased or decreased indirectly via the ambient air. Advantageously, the air conditioning system can also dry fibers or air.

[0054] The combination of direct humidification and indirect climate control is particularly advantageous. For example, a humidification system can spray a liquid onto the fibers. The increased humidity allows the fibers to dissipate their electrostatic charge. Additionally, in a climate control area (e.g., one prone to corrosion), dry ambient air can maintain an optimal humidity level. Targeted humidification of the fibers can be especially beneficial in process sections where unwanted fiber shedding is likely.

[0055] The climate-controlled area of ​​the nonwoven fabric production plant is advantageously localized. A separate climate control area increases the energy efficiency of the plant, especially compared to climate control of an entire hall.

[0056] The positioning instruction preferably includes a setpoint for a liquid quantity, a temperature setting, or a humidity setting. Alternatively or additionally, positioning instructions can include setpoints for mechanical actuators (e.g., speed for a drive, angle for a guide, position of a positioning range, movement specifications).

[0057] The system components have suitable interfaces for receiving and / or transmitting commands.

[0058] Advantageously, multiple detection or control devices can be used for separate fiber streams (fiber sources). Differences between the properties of different fiber streams can be detected and compensated for.

[0059] The detection zone can be located at various points within the nonwoven fabric production plant. It is advantageous to position a detection zone at the outlet of a pile-forming unit (e.g., carding, airlay, spunbond unit) or a fiber preparation unit (e.g., bale breaker, fiber opener, metering unit, fiber blending unit). Multiple detection zones, particularly those with multiple detection units, can be arranged along the production process. For example, a detection zone can be located in a bale breaker, downstream of a fiber blending unit, and / or at the outlet of a flaker feeder.

[0060] In a first embodiment, the monitoring technology can be used for quality assurance purposes. The recorded properties of the nonwoven pre-product are processed in a data processing unit. The acquisition results can include raw measurement data or pre-processed property data. Data processing algorithms can be used to enrich the measurement data with temporal and spatial information. Furthermore, patterns in the temporal or spatial progression of the acquisition results can be identified. The acquisition results can be stored in a memory, in particular a suitable database for quality assurance purposes, or displayed on a suitable display device, e.g., a central plant terminal.This processing method is advantageous because undesirable properties can be identified in the nonwoven pre-product at an early stage of the production process.

[0061] Preferably, a cross-sectional analysis is performed based on the data collection results. -and / or longitudinal profiles of the properties are generated. The longitudinal profile can, in particular, include a temporal and / or spatial progression of the properties along the production direction. The transverse profile comprises a progression of the properties across the width of the nonwoven pre-product and / or a fiber stream. Preferably, location and / or time information is stored for each recorded property. For example, the location of a measurement in linear meters relative to a reference location (e.g., linear meters since the start of production) can be stored. A production time (e.g., date and time) can also be linked to the recorded properties. Linking the recorded properties to the measurement location is particularly advantageous for precise control or regulation of the properties.

[0062] In another embodiment, the monitoring technology can be used for adjusting the nonwoven pre-production plant, particularly for control purposes. The recorded properties can be compared with target properties to identify deviations.

[0063] Using suitable decision rules, setup instructions are generated for configuring the nonwoven fabric pre-production plant. The generation of these setup instructions can take into account both the recorded properties and target properties, as well as any identified property deviations and / or other process parameters.

[0064] Positioning instructions are generated for setting fiber preparation equipment and, in particular, pile formation equipment. Specifically, the properties of the nonwoven pre-product can be controlled by adjusting the nonwoven pre-production system. This control can also take into account additional information, e.g., from other sensors in the system. For example, the fiber openness can be measured and controlled by adjusting one or more fiber opener devices. Suitable positioning instructions are generated and transmitted either to a system controller, directly to a fiber preparation or pile formation unit, or to a suitable positioning device.

[0065] Based on the positioning instructions, actuators in the nonwoven pre-production plant can modify the fiber preparation or pile formation process in such a way that the measured properties change in the desired direction. For example, a positioning instruction can be transmitted to an actuator on the feed chute of a flaker feeder. Using an actuator, such as an electric motor, the width of the feed chute is adjusted according to the positioning instruction.

[0066] Suitable control algorithms will be used to regulate the properties of the nonwoven pre-product by adjusting the nonwoven pre-production plant. Both simple linear and complex nonlinear controllers can be used to generate the setup instructions. In particular, trained artificial neural networks or fuzzy controllers can be used to process the acquisition data and generate appropriate setup instructions.

[0067] The invention is illustrated in the drawings in an exemplary and schematic manner. They show: Figure 1: a schematic representation of a nonwoven pre-production plant (10) with monitoring device (40), a central plant control (11) and an air conditioning system (12); Figure 2: a schematic representation of a nonwoven pre-production plant (10) with a feeder (31), a carding machine (32) and an adjustment device (50); Figure 3: a schematic representation of a nonwoven manufacturing plant (15) with a nonwoven pre-production plant (10) as well as a nonwoven layer (91) and a nonwoven bonding device (92); Figure 4: a schematic top view of a nonwoven pre-product (3) between a pile formation device (30) and a further processing device (90); Figure 5: a schematic representation of a nonwoven pre-production plant (10) with an air-conditioned carding machine (30) and several humidification devices (24).

[0068] A nonwoven fabric production plant (15) can be configured with a varying number of machines depending on the nonwoven fabric to be produced. The nonwoven fabric production plant (15) comprises a nonwoven pre-production plant (10) for the production of a nonwoven pre-product (3) and one or more downstream processing plants (90) for processing the nonwoven pre-product (3) into the finished nonwoven fabric (7). Various conveying devices can be used for transporting the fibers or the fiber pile between the individual machines.

[0069] Figure 1 Figure 1 shows a nonwoven fabric production plant (15) comprising a nonwoven fabric pre-production plant (10) and a downstream processing plant (90). The nonwoven fabric pre-production plant (10) includes a fiber preparation plant (20), a pile formation plant (30), and a monitoring plant (40). Preferably, the nonwoven fabric production plant (15) also includes a plant control system (11).

[0070] In the nonwoven pre-production plant (10), fibers (1) are processed in one or more fiber preparation units (20). The processed fibers (2) are then used to form a nonwoven pre-product (3) in one or more pile-forming units (30). The nonwoven pre-product (3) consists of an unprocessed fiber pile.

[0071] The monitoring device (40) has a detection device (41) with one or more sensors (410) for detecting the properties of the nonwoven pre-product (3). The properties of the nonwoven pre-product (3), in particular its moisture content, electrical charge, weight distribution, fiber orientation, fiber mixing ratio and / or fiber openness, are detected in a detection area (5).

[0072] The arrangement of the capture area (5) close to the exit of the nonwoven pre-product (3) from the pile-forming unit (30) is particularly advantageous. The capture unit (41) and / or the capture area (5) can be located both inside and outside the pile-forming unit (30).

[0073] Downstream of the capture area (5) in the production direction (4), one or more downstream processing units (90) are located. The downstream processing units (90) further process the nonwoven pre-product (3) into the finished nonwoven fabric (7) in one or more processing steps. During downstream processing, the structure of the fiber pile is modified. In particular, the pile can be layered in several layers in a lay-up unit (91) to increase the pile thickness. The fiber orientation can also be changed during downstream processing. Other properties can also be modified by the downstream processing downstream of the capture area (5).

[0074] Parts of the nonwoven pre-production plant (10) are preferably air-conditioned. This embodiment is particularly advantageous in regions with humid climates in order to influence the moisture content and / or temperature of the fibers or the nonwoven pre-product (3). The nonwoven production plant (15) can have one or more air conditioning units (12). Preferably, the process zone within the fiber preparation unit (20) and / or the nonwoven formation unit (30) is air-conditioned. Alternatively, the entire production hall can be air-conditioned by one air conditioning unit (12). In this preferred embodiment, the air conditioning unit (12) is adjustable via the plant control system (11). Alternatively, the air conditioning unit (12) can also directly receive positioning instructions (45) from the monitoring unit (40).

[0075] The detection device (41) performs measurements on the nonwoven pre-product within the detection area (5). One or more sensors (410) can be moved across the nonwoven pre-product (3). The movement of a sensor (410) can be along or across the conveying direction of the nonwoven pre-product (3). The movement of a sensor (410) can be controlled depending on the conveying speed of the nonwoven pre-product (3) within the detection area (5). This is particularly advantageous for facilitating the assignment of the detection results to the corresponding section of the moving nonwoven pre-product (3). Individual or all sensors (410) can also be arranged in a stationary position. The stationary arrangement is particularly advantageous for local measurements, e.g., of the moisture content of the nonwoven pre-product (3). The sensors (410) can be arranged both above and below the nonwoven pre-product.In an alternative embodiment, the detection area (5) can also be located within the floret-forming device (30), in particular a teasel.

[0076] The measurements using a sensor (410) are non-contact. Infrared sensors are preferably used. Other non-contact measurement methods using cameras or other active radiation sources, e.g., for X-rays, are also possible. The detection device (40) is designed to arrange suitable sensors (410) on the nonwoven pre-product (3) in such a way that its properties can be reliably detected.

[0077] A monitoring device (40) also includes a data processing unit (42). The data processing unit (42) can comprise a digital storage device with a data processing program and a processor. The data processing unit (42) is configured to process acquisition results from the acquisition unit (41), in particular to execute processing steps of the claimed monitoring method. The data processing unit (42) can also be configured as an embedded system of the acquisition device (410) or as part of the plant control system (11). The monitoring device (40) with the data processing unit (42) is configured to carry out the claimed monitoring method.

[0078] The monitoring device (40) is specifically designed to generate control instructions (45) for setting the nonwoven pre-production plant (10). Preferably, the monitoring device (40) controls the properties of the nonwoven pre-product (3). The control instructions (45) can be generated according to a control algorithm. The control instructions (45) preferably contain the manipulated variables for a closed-loop control system. The controller is preferably implemented in the monitoring unit (40), particularly in the data processing unit (42). Based on the suitable control instructions (45), the manufacturing process within the nonwoven pre-production plant (10) is adjusted such that the properties of the nonwoven pre-product (3) change in the desired manner. In another embodiment, the control instructions (45) can also be used for control in an open-loop control system or for feedforward control.

[0079] In this preferred embodiment, the setup instructions (45) are transmitted to the plant control unit (11). The plant control unit (11) can serve for the general control and monitoring of the entire nonwoven fabric production plant (15). It is specifically designed to process setup instructions (45) for monitoring, and in particular controlling, the properties of the nonwoven pre-product (3). The plant control unit (11) can, in particular, include driver stages to convert signal streams from the setup instructions (45) into power streams. Alternatively, the driver stages can also be arranged on another part of the nonwoven pre-production plant (10), in particular on a fiber preparation unit (20) or a pile formation unit (30). The central plant control unit (11) can, in particular, communicate with various parts of the nonwoven pre-production plant (10), especially with the monitoring unit (40), via a bus network.

[0080] To generate suitable setting instructions (45), the monitoring device (40) can process additional information from the nonwoven fabric production plant (10) besides the data acquired by the acquisition device (41). In particular, target properties of the nonwoven pre-product (3) can be obtained or entered by a user. The monitoring device (40) is designed to detect deviations between the acquired properties and the target properties of the nonwoven pre-product (3). Target properties can be fixed or variable values ​​or ranges. For example, the target moisture content of the nonwoven pre-product can be specified with a range between a minimum and a maximum moisture content. Both the acquired and the target properties can be deterministic values ​​and / or statistical values. Properties of the nonwoven pre-product (3) can also be spatial and / or temporal distributions.

[0081] Controlling the properties of the nonwoven pre-product (3) to predetermined target properties is particularly advantageous for achieving high quality in the finished nonwoven fabric (7). A high-quality nonwoven pre-product (3) is beneficial for further processing. Certain properties of the pile, especially the fiber openness or fiber orientation, are determined at an early stage of the production process, particularly by fiber preparation equipment (20) and pile formation equipment (30). Early detection of these properties along the production direction (4) improves the control options. Furthermore, certain properties can be better detected before the first processing step that alters the pile structure. In particular, measurement methods that measure radiation penetrating the pile can provide better information about the properties of a thin and unbonded pile.An arrangement of the detection area (5) along the production direction (4) in front of a first nonwoven layer (91) and / or a needling machine is therefore advantageous. Short pile cycle times between pile formation and detection area (5) also lead to improved control dynamics.

[0082] By automatically adjusting a nonwoven fabric pre-production plant (10) based on the data from the monitoring device (40), the plant's efficiency can also be improved. Setup times can be shortened and the amount of rejects reduced.

[0083] Figure 2Figure 40 shows a further embodiment of a nonwoven pre-production plant (10). The monitoring device (40) generates positioning instructions (45) and transmits them directly to a fiber preparation device (20) and / or to a pile formation device (30). The pile formation device (30) preferably comprises a carding unit (32) and a feeder (31). The feeder (31) supplies the carding unit (32) with prepared fibers (2). In the feeder (31), a continuous fiber stream is formed from the prepared fibers (2), which can be processed into a pile in a carding unit. The feeder (31) has guides and conveying means for the fibers, which can be used to influence the fiber stream. For example, the cross-section of the feeder chute in the feeder (31) can be changed. An adjusting device (50) adjusts the fiber guides according to a positioning instruction (45).

[0084] The positioning device (50) can comprise a driver stage and actuators, in particular an electric motor. Positioning devices (50) are preferably arranged on a fiber preparation unit (20) or on a pile formation unit (30). The positioning devices (50) can have a uniform interface for receiving positioning instructions (45). The interface can be compatible with a bus system of the pile formation unit (10) and communicate via it. Instead of its own actuator, the positioning device (50) can also have a special machine interface via which the actuators of the nonwoven pre-production unit are controlled. The positioning device (50) can serve as a unified interface for positioning instructions (45) to various actuators. This is particularly advantageous if the nonwoven pre-production unit consists of machines from different manufacturers.

[0085] The monitoring technology can be supplied as a retrofit component for existing nonwoven fabric production plants. The use of standardized interfaces on the actuators (50) for transmitting actuator instructions (45) is particularly advantageous in this case, as only the actuators need to be adapted to existing machines.

[0086] Figure 3 Figure 1 shows a nonwoven pre-production plant (10) with a special fiber preparation unit (20). Various fiber types (1) are processed into a pile in this plant. The fiber preparation unit (20) includes a fiber mixing unit (22) in which the different fiber types (1) are mixed.

[0087] The fiber mixing device (22) is preferably designed to be adjustable by means of setting instructions (45). This is particularly advantageous for changing or controlling the measured fiber mixing ratio of the nonwoven pre-product (3).

[0088] The fibers (1) are typically fed into the system in the form of compressed bales. The illustrated embodiment has bale breakers (21) in which the fibers are separated from the bales. Fiber clumps are opened in one or more steps. The fiber processing unit (20) can have one or more bale breakers (21) and / or fiber opening devices (23). With this fiber processing unit (20), the fibers (1) can be processed in such a way that a pile can be formed from them in a pile-forming unit (30), in particular a mechanical or aerodynamic carding machine (32). The pile-forming unit (30) can also include (additional) fiber opening devices, in particular fine openers for multi-stage fiber opening processes.

[0089] Both the bale breakers (21) and the fiber opening devices (23) are adjustable. The fiber preparation process can be adjusted using the setting instructions (45). This is particularly advantageous when controlling the degree of fiber opening of the nonwoven pre-product (3).

[0090] The fiber preparation unit (20) can also include a humidification unit (24) (also called a smelting station). In a smelting station, fibers can be treated with various chemical agents, in particular by wetting or spraying them with liquids. For example, an antistatic agent can be sprayed onto the fibers to prevent or reduce their static charge. Other chemical treatments are also possible. The humidification unit is also adjustable. In particular, the moisture content of the fibers can be influenced by adjusting the humidification unit.

[0091] Figure 4Figure 1 shows a top view of a nonwoven pre-product (3) between a pile-forming device (30) and a processing device (90). Properties of the nonwoven pre-product (3) are detected within a detection area (5) by means of a monitoring device (40). The figure shows a preferred embodiment of a detection device (41) with a movable sensor (410). Also indicated is an embodiment with a sensor bar (411) extending across the width of the nonwoven pre-product.

[0092] The nonwoven pre-product (3) is continuously conveyed in the production direction (4). The conveying movement of the web (3) and the movement of the sensor (410) shift the detection area (5) on the web (3). This results in a trajectory (5) of locations where the properties of the nonwoven pre-product are measured. Measurements are taken over time in a zigzag or wave pattern, particularly across the entire width of the web (3).

[0093] From the recorded properties, a profile (6) of the properties can be determined, in particular across the width of the nonwoven pre-product (3) perpendicular to the production direction (4). The profile describes the distribution of the properties of the nonwoven pre-product.

[0094] A recorded property at a recording location (5i) is preferably provided with location information and / or time information.

[0095] By recording the properties and / or a spatial or planar distribution of the properties, an automated adjustment can be made at an adjusting device (50) of a pile formation device (30) (e.g. a carding machine or a feeding shaft) or a fiber preparation device (20).

[0096] Preferably, an adjustment is made on an adjusting device (50) designed to locally influence the properties of the nonwoven pre-product (3). In the illustrated embodiment, the feeder chute of a feeder (31) is adjusted. The feeder chute preferably has adjusting devices designed to adjust the fiber flow across the entire width and / or at individual points along the width of the nonwoven pre-product. By adjusting the feeder chute, the basis weight of the nonwoven pre-product can be controlled or regulated locally, across the entire surface, and / or globally.

[0097] Alternatively or additionally, further adjusting devices (50) can be automatically adjusted on a fiber preparation plant (20) or a pile formation device (30), for example a bale breaker, the set of a carding machine (32), a dosing device or a fiber opener.

[0098] Preferably, the capture area (5) is arranged downstream of a first carding unit (32). In a further embodiment, the capture area (5) is arranged downstream of a second, third, or further carding unit (32) or other pile-forming device (30) in the production direction (4). In certain applications, the nonwoven pre-product (3) can be placed between several pile-forming steps (e.g., carding). In this embodiment, the nonwoven pre-product (3) in the capture area (5) is a laid and unbonded fiber pile. The subsequent processing that alters the structure can relate to one or more properties of the nonwoven pre-product.

[0099] Preferably, the detection area (5) is arranged downstream of the last card (32) in the production direction (4). Preferably, the detection area (4) is arranged upstream of a first consolidation unit. During consolidation, the cohesion between the fibers of the nonwoven pre-product is strengthened.

[0100] The nonwoven pre-product can consist of a single- or multi-layered fiber pile. During the pile formation process, the fiber pile can be layered on top of each other, thereby increasing its thickness.

[0101] Figure 5 shows a schematic representation of a nonwoven pre-production plant (10) with various embodiments of a monitoring technology, in particular for moisture and / or electrical charge.

[0102] The figure shows a possible embodiment of an air conditioning area (13). A napkin formation device (30) (e.g., a teasel (32)) includes an air conditioning unit (12). The air conditioning unit (12) is configured to adjust the ambient conditions, in particular the absolute or relative humidity and / or the temperature, within an air conditioning area (13). In this advantageous embodiment, the air conditioning area is integrated into the teasel (32). The teasel housing is essentially climatically separated from the environment.

[0103] The nonwoven fabric production plant can include one or more air conditioning areas (13) or air conditioning units (12). The air conditioning area (13) can also be built around a machine (e.g., for retrofitting).

[0104] The nonwoven pre-production plant (10) can include one or more humidification units (24). The humidification unit (also called a sizing station) is designed to apply a liquid or grease to fibers. The humidification unit (24) can, in particular, include a spray nozzle or other humidifying agents. Preferably, distilled water is sprayed. A mist can also be formed. Alternatively or additionally, a chemical, an additive, or a lubricant can be applied in a humidification unit (24). A humidification unit (24) can be combined with an air conditioning system (12). Advantageously, the humidification unit includes one or more liquid tanks and / or controllable pumps. The air conditioning system (12) can, alternatively or additionally, provide desiccants. (e.g. an infrared lamp, fan or heater).

[0105] The humidification device (24) can in particular be integrated into a machine a fiber preparation device (20) or a pile formation device (30).

[0106] An air conditioning system (12) and / or a humidification system (24) includes a control device (50). The control device (50) is configured to receive control instructions (45). Furthermore, the control device (50) is configured to control the moisture input (e.g., by dosing a liquid) and / or the moisture removal (e.g., by adjusting the temperature or irradiation).

[0107] The figure shows several possible arrangements of a detection area (5) or a detection device (41). In particular, the properties of a fiber stream can be detected downstream of, inside, or on a bale breaker (21), downstream of, inside, or on a fiber mixing device (22), or on another fiber processing device (20). Preferably, the properties are detected in a detection area (5) that is arranged downstream of an actuating device (50) in the production direction (4). With such an arrangement, the properties can advantageously be controlled in a feedback loop. Alternatively or additionally, the properties can also be controlled.

[0108] The recorded properties of the nonwoven pre-product can also be used for other purposes, such as predictive maintenance and / or damage detection. In an advantageous embodiment, the recorded properties are analyzed automatically. Preferably, the frequency behavior of the properties is analyzed. In particular, a Fourier transform can be applied to the recorded properties. The frequencies of the recorded properties can be compared with frequencies of periodic movements (e.g., rotational speeds of rotating or oscillating parts) or known machine parameters. In a preferred embodiment, damage to a component is detected by frequency patterns in the recorded properties. An automated warning about an unusual frequency behavior can be generated. In particular, a warning about damage or maintenance requirements for a specific component can be generated.

[0109] The nonwoven pre-product is a sheet-like and / or web-like fiber mat. The width of the nonwoven pre-product is preferably 1m to 4m.

[0110] Preferably, the monitoring device includes an infrared sensor. Alternatively or additionally, radioactive radiation sensors or X-ray sensors can be used. In particular, isotope backscatter sensors are also suitable. Radioactive radiation from a krypton isotope is especially suitable for detecting the properties of a nonwoven fabric precursor.

[0111] The use of radioactive radiation requires special radiation protection measures. After a half-life, the sensors or the radiation source typically need to be replaced. Infrared sensors have the advantage of also being able to detect moisture. Furthermore, infrared sensors require less maintenance. Depending on the type of nonwoven product, different sensors may be advantageous. The specific detection range and the application of the detection results are beneficial when combined with various sensor types.

[0112] In a preferred embodiment, the monitoring device (40) is configured with the detection device (41) and its own data processing unit (42). This embodiment has the advantage that the monitoring method can be implemented in existing systems by retrofitting a monitoring device (40). This allows product quality to be improved even in existing systems. In a further embodiment, the monitoring device (40) can be configured as a distributed system. In particular, the detection device (41), the data processing unit (42), and the actuating device (50) can each be configured in separate hardware units. The data processing unit can, in particular, be implemented in a plant control system.

[0113] Variations of the invention are possible in various ways. In particular, the features shown, described, or claimed for the respective embodiments can be combined, replaced, supplemented, or omitted in any way.

[0114] The disclosure includes, as an independent aspect that can be applied on its own or in combination with the aspect to which the independent claims are directed, a monitoring technique with the following features. REFERENCE MARK LIST

[0115] 1 Fibers Fibers 2 (Processed) fibers (Pre-processed) fibres 3 Nonwoven pre-product, pile roll Nonwoven pre-product 4 Production direction Production direction 5 Detection area Detection zone 5i Local recording location Local detection spot 6 Property profile Property profile 7 nonwoven fabric Nonwoven fabric 10 Nonwoven fabric pre-production plant Nonwoven pre-production plant 11 Plant control Plant control unit 12 air conditioning Air conditioning system 13 air conditioning area Air-conditioned zone 15 Nonwoven fabric production plant Nonwoven fabrication plant 20 Fiber processing equipment Fiber processing facility 21 Ball breaker Bale opener 22 Fiber mixing device Fibre blending facility 23 Fiber opening device Fiber opening facility 24 humidification system Moistening unit 30 Flower formation facility Web forming facility 31 Speiser Feeder 32 teasel Card 40 Monitoring device Control unit 41 Recording device Detection unit 410 sensor sensor 411 Sensor bars Sensor beam 42 Data processing unit Data processing unit 45 Positioning instructions Actuation command 46 Parking area Actuation zone 50 Actuator Actuation unit 90 Further processing equipment Web processing facility 91 Fleece layer Cross lapper 92 Nonwoven bonding device Web bonding facility

Claims

1. Monitoring method for a production process of a nonwoven pre-product, wherein the properties of a nonwoven pre-product (3), in particular the basis weight, the fibre orientation, the fibre blend ratio, the fibre opening degree, the moisture content, and / or the electrical charge, are detected by a detection unit (41) in a detection zone (5), and the detection results are processed in a data processing unit (42), wherein the nonwoven pre-product (3) in the detection zone (5) is a fibrous web that is unprocessed, and the properties of the nonwoven pre-product (3) are detected across the width of the nonwoven pre-product (3) transverse to the production direction (4), and actuation commands (45) are generated for the configuration of a fibre processing facility (20) for control and / or regulation of the detected properties of the nonwoven pre-product (3).

2. Monitoring method according to claim 1, characterized in that the detection zone (5) is located directly at or near the outlet of the nonwoven pre-product (3) from a web forming facility (30), in particular a flatbar carding machine, roller carding machine, air lay machine, or spunbond machine.

3. Monitoring method according to claim 1 or 2, characterized in that the detection zone (5) is located along the production direction (4) ahead of a facility (90) for subsequent processing by web structure altering, in particular a cross lapper (91) or a bonding facility (92).

4. Monitoring method according to one of the preceding claims, characterized in that the spatial distribution of properties of the nonwoven pre-product (3) longitudinal and / or transverse to the production direction (4) is detected, in particular with a movable sensor (410) or a fixed sensor beam (411).

5. Monitoring method according to one of the preceding claims, characterized in that the detection results are compared with the target properties of the nonwoven pre-product (3) and property deviations are determined.

6. Monitoring method according to one of the preceding claims, characterized in that actuation commands (45) are generated for a nonwoven pre-production plant (10), in particular a fibre processing facility (20) and a web forming facility (30).

7. Monitoring method according to one of the preceding claims, characterized in that actuation commands (45) are generated which are designed to influence and / or configure and / or regulate properties of the nonwoven pre-product (3) locally in an actuation zone (46), in particular in a section of the width of the nonwoven pre-product (3) transverse to the production direction.

8. Monitoring method according to one of the preceding claims, characterized in that a property of the nonwoven pre-product (3), in particular a local property or the spatial and / or area distribution of a property transverse and / or longitudinal to the production direction (4), is regulated or controlled.

9. Monitoring method according to one of the preceding claims, characterized in that a process parameter, in particular a fiber volume flow, the speed of a fibre conveyor, the pose of a fibre guiding system, or the air conditioning, is changed at the nonwoven pre-production plant (10), in particular at a fibre processing facility (20) and / or a web forming facility (30).

10. Monitoring method according to one of the preceding claims, characterized in that the basis weight, in particular the spatial and / or area distribution longitudinal and / or transverse to the production direction (4) of the nonwoven pre-product (3) is specifically influenced by configuring the fibre conveyance speed of the nonwoven pre-production plant (10), the feeder performance of a feeder (31), or the intake of a web forming facility (30).

11. Monitoring method according to one of the preceding claims, characterized in that the fibre orientation in the nonwoven pre-product (3) is specifically influenced by configuring a web forming facility (30), in particular of a rolled card or aerodynamic card (air lay).

12. Monitoring method according to one of the preceding claims, characterized in that the blend ratio of the fibre components in the nonwoven pre-product (3) is specifically adjusted by configuring a bale opener (21), a dosing device, a fibre opening facility (23), or a fibre blending facility (22).

13. Monitoring method according to one of the preceding claims, characterized in that the opening degree of the fibers in the nonwoven pre-product (3) is specifically influenced by configuring a fibre opening facility (41) or a web forming facility (30).

14. Monitoring unit (40) for a nonwoven fabrication plant, wherein the monitoring unit (40) has a detection unit (41) for detecting properties of a nonwoven pre-product (3), in particular the basis weight, the fibre orientation, the fibre blend ratio, the fibre opening degree, the moisture content, and / or the electrical charge, in a detection zone (5), and a data processing unit (42), wherein the detection unit (41) comprises one or more sensors (410), in particular an infrared sensor, a radioactive radiation sensor and / or an X-ray sensor, wherein the detection unit (41) is designed to detect properties of an unprocessed nonwoven pre-product (3) across the width of the nonwoven pre-product (3) transverse to the production direction (4), and the monitoring unit (40) is designed to generate actuation commands (45) for configuring a fibre processing facility (20) to control and / or regulate the detected properties of the nonwoven pre-product (3).

15. Nonwoven pre-production plant (10) with a fibre processing facility (20) and a web forming facility (30) for forming a nonwoven pre-product (3) characterized in that the nonwoven pre-production plant (20) comprises a monitoring unit (40) according to claim 14 and is designed to perform a monitoring method according to one of claims 1 to 13.