MONITORING PROCESS FOR NONWOVEN FABRICATION PLANTS

Abstract

A monitoring process is provided for a method for producing a nonwoven product. Properties of a nonwoven pre-product (3), in particular the humidity, the electric charge, the weight distribution, the fiber orientation, the fiber mixing ratio and/or the fiber opening degree of an unprocessed fiber web, are detected by a detection unit (41) having one or more sensors (410).

Claims

1. A monitoring process for a process for producing a nonwoven pre-product, the monitoring process comprising: detecting properties of a nonwoven pre-product, including one or more of weight per unit area, fiber orientation, fiber-blending ratio fiber opening degree, moisture content, temperature and electrical charge, with a detection unit in a detection zone; processing detection results in a data processing unit, wherein the nonwoven pre-product in the detection zone is still an unprocessed fiber web and the properties of the nonwoven pre-product are detected over the width of the nonwoven pre-product across a production direction; and generating actuation commands fora nonwoven pre-production plant comprising a fiber processing device or a web forming device or both a fiber processing device and a web forming device.

2. A monitoring process in accordance with claim 1, wherein the detection zone is located directly at or close to the discharge of the nonwoven pre-product from the web forming device comprising a card, airlay or spunbond machine.

3. A monitoring process in accordance with claim 1, wherein the detection zone is located in the production direction in front of the web structure-changing web processing device comprising a cross lapper or a bonding device.

4-5. (canceled)

6. A monitoring unit in accordance with claim 1 wherein the three-dimensional distribution of properties of the nonwoven pre-product is detected along and or across the production direction with a movable sensor or with a stationary sensor beam.

7-8. (canceled)

9. A monitoring process in accordance with claim 1 wherein a frequency analysis of the detection results is carried out, especially on the basis of a Fourier transformation.

10. A monitoring process in accordance with claim 9, wherein a damage to or a need for maintenance of a component of the nonwoven pre-production plant is determined on the basis of frequency analysis, comprising a comparison of a periodic movement of the component and frequency analysis of the detection results.

11. A monitoring process in accordance with claim 1, wherein the detection results are compared with desired properties of the nonwoven pre-product and deviations of the properties are determined.

12. (canceled)

13. A monitoring process in accordance with claim 1, wherein actuation commands are generated, which are configured to influence and/or to set and/or to regulate properties of the nonwoven pre-product locally in an actuation zone in a partial area of a width of the nonwoven pre-product across the production direction.

14. A monitoring process in accordance with claim 1, wherein a local property of the nonwoven pre-product or the three-dimensional and/or two-dimensional distribution of a property across and/or along the production direction, is regulated or controlled.

15. (canceled)

16. A monitoring process in accordance with claim 1, wherein a process parameter comprising a fiber volume flow, a speed of a conveying device, a position of a fiber guide mechanism, or air conditioning, is changed at the fiber processing device and/or at the web forming device.

17. A monitoring process in accordance with claim 1, wherein by changing a process parameter, a detected property of the nonwoven pre-product is influenced to compensate deviations of properties.

18. (canceled)

19. A monitoring process in accordance with claim 1, wherein the weight per unit area, especially a three-dimensional and/or two-dimensional distribution along and/or across the production direction, of the nonwoven pre-product is influenced in a specific manner by setting the fiber conveying speed of the nonwoven pre-production plant, the feed characteristic of a feeder or the inlet of a web forming device.

20. A monitoring process in accordance with claim 1, wherein the fiber orientation in the nonwoven pre-product is influenced in a specific manner by setting the web forming device, including a card or aerodynamic card (airlay).

21. A monitoring process in accordance with claim 1, wherein the fiber blending ratio of the fiber components in the nonwoven pre-product is set in a specific manner by setting a bale opener, a dispensing device, a fiber opening device or a fiber blending device.

22. A monitoring process in accordance with claim 1, wherein the opening degree of the fibers in the nonwoven pre-product is influenced in a specific manner by setting a fiber opening device or the web forming device.

23. (canceled)

24. A monitoring unit for a nonwoven fabrication plant, the monitoring unit comprising: a detection unit configured to detect properties of a nonwoven pre-product in a detection zone, wherein the detection unit comprises one or more of an infrared sensor, a radioactive radiation sensor and an X-ray sensor, wherein the detection unit is configured to detect properties of an unprocessed nonwoven pre-product over a width of the nonwoven pre-product across a production direction; and a data processing unit configured to generate actuation commands for a nonwoven pre-production plant comprising a fiber processing device or a web forming device or both a fiber processign device or a web forming device.

25-28. (canceled)

29. A monitoring unit in accordance with claim 24, wherein the one or more sensor of the detection unit is movable along and/or across the production direction over the nonwoven pre-product.

30-31. (canceled)

32. A nonwoven pre-production plant comprising a fiber processing device; a web forming device cooperating with the fiber processing device for forming a nonwoven pre-product; and a monitoring unit comprising: a detection unit configured to detect properties of the nonwoven pre-product in a detection zone, wherein the detection unit comprises one or more of an infrared sensor, a radioactive radiation sensor and an X-ray sensor, wherein the detection unit is configured to detect properties of an unprocessed nonwoven pre-product over a width of the nonwoven pre-product across a production direction; and a data processing unit configured to generate actuation commands for a nonwoven pre-production plant comprising a fiber processing device or a web forming device or both a fiber processing device or a web forming device.

33. A nonwoven pre-production plant in accordance with claim 32 wherein the fiber processing device and/or a web forming device is set by the monitoring unit to regulate, properties of the nonwoven pre-product.

34. A nonwoven pre-production plant according to claim 32 in combination with one or more web structure-changing web processing devices to form a nonwoven fabrication plant for producing a nonwoven fabric, wherein the one or more web structure-changing web processing devices comprises a cross lapper or a web bonding device or a cross lapper and a web bonding device, wherein the detection zone of the monitoring unit is located between a web forming device of the nonwoven pre-production plant and a web processing device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0064] In the drawings:

[0065] FIG. 1 is a schematic view of a nonwoven pre-production plant with monitoring unit, with a central plant control unit and with an air conditioning system;

[0066] FIG. 2 is a schematic view of a nonwoven pre-production plant with a feeder, with a card and with an actuating unit;

[0067] FIG. 3 is a schematic view of a nonwoven fabrication plant with a nonwoven pre-production plant as well as with a cross lapper and with a web bonding device;

[0068] FIG. 4 is a schematic top view of a nonwoven pre-product between a web forming device and a web processing device; and

[0069] FIG. 5 is a schematic view of a nonwoven pre-production plant with an air-conditioned card and with a plurality of moistening units.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0070] Referring to the drawings, a nonwoven fabrication plant (15) may be configured with different numbers of machines depending on the nonwoven fabric to be produced. The nonwoven fabrication plant (15) comprises a nonwoven pre-production plant (10) for producing a nonwoven pre-product (3) as well as one or more web processing devices (90) for processing the nonwoven pre-product (3) into the finished nonwoven fabric (7). Different conveying devices may be used to transport the fibers and the fiber web between the individual machines.

[0071] FIG. 1 shows a nonwoven fabrication plant (15) with a nonwoven pre-production plant (10) and with a web processing device (10). The nonwoven pre-production plant (10) comprises a fiber processing device (20), a web forming device (30) as well as a monitoring unit (40). The nonwoven fabrication plant (15) preferably has, in addition, a plant control unit (11).

[0072] Fibers are processed in one or more fiber processing devices (20) in the nonwoven pre-production plant (10). A nonwoven pre-product (3) is then formed from the pre-processed fibers (2) in one or more web forming devices (30). The nonwoven pre-product (3) comprises a still unprocessed fiber web.

[0073] The monitoring unit (40) has a detection unit (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), especially the moisture content, the electrical charge, the weight distribution, the fiber orientation, the fiber blending ratio and/or the fiber opening degree thereof, are detected in a detection zone (5).

[0074] Arrangement of the detection zone (5) near the discharge of the nonwoven pre-product (3) from the web forming device (30) is especially advantageous. The detection unit (41) and/or the detection zone (5) may be located both within and outside the web forming device (30).

[0075] One or more web processing devices (90) follow after the detection zone (5) in the production direction. The nonwoven pre-product (3) is processed further into the finished nonwoven fabric (7) in one or more processing steps with the web processing devices (90). The structure of the fiber web is changed during the further processing. In particular, the web may be placed in a plurality of layers one on top of another in a cross lapper (91) in order to increase the thickness of the web. Especially the fiber orientation may change during the further processing. Other properties may also be changed by the further processing after the detection zone (5).

[0076] Parts of the nonwoven pre-production plant (10) are preferably air-conditioned. Especially in regions with humid climate, the embodiment is advantageous for influencing the moisture content and/or the temperature of the fibers and of the nonwoven pre-product (3). The nonwoven fabrication plant (15) may have one or more air conditioning systems (12). The process zone within the fiber processing device (20) and/or within the web forming device (30) is preferably air-conditioned. As an alternative, the entire production hall may be air-conditioned by an air conditioning system (12). The air conditioning system (12) can be set with the plant control unit (11) in this preferred embodiment. The air conditioning system (12) may, as an alternative, also receive actuation commands (45) directly from the monitoring unit (40).

[0077] The detection unit (41) carries out measurements on the nonwoven pre-product in the detection zone (5). One or more sensors (410) can be moved to and fro over the nonwoven pre-product (3). The movement of a sensor (410) may take place along or across the conveying direction of the nonwoven pre-product (3). The movement of a sensor (410) may be controlled as a function of the conveying speed of the nonwoven pre-product (3) in the detection zone (5). This is especially advantageous for facilitating an assignment of the detection results to the corresponding section of the running nonwoven pre-product (3). Individual sensors (410) or all sensors (410) may also be arranged stationarily. Especially advantageous is the stationary arrangement for local measurements, e.g., of the moisture content of the nonwoven pre-product (3). The sensors (410) may be arranged both above and under the nonwoven pre-product. In an alternative embodiment, the detection zone (5) may also be located within the web forming device (30), especially a card.

[0078] The measurements by means of a sensor (410) take place in a contactless manner. Infrared sensors are preferably used. Other contactless measuring methods with cameras or other active radiation sources, e.g., for X-ray, are also possible. The detection unit (41) is configured to arrange suitable sensors (410) at the nonwoven pre-product (3) such that the properties of the nonwoven pre-product can be reliably detected.

[0079] A monitoring unit (40) has, in addition, a data processing unit (42). The data processing unit (42) may comprise a digital memory with a data processing program and with a processor. The data processing unit (42) is configured to process detection results of the detection unit (41), especially in order to carry out processing steps of the monitoring process disclosed herein. The data processing unit (42) may also be configured as an embedded system of the detection unit (41) or as a part of the plant control unit (11). The monitoring unit (40) with the data processing unit (42) is configured to carry out the monitoring process being disclosed.

[0080] The monitoring unit (40) is configured especially to generate actuation commands (45) for setting the nonwoven pre-production plant (10). The monitoring unit (40) preferably regulates the properties of the nonwoven pre-product (3). The actuation commands (45) may be generated according to a control algorithm. The actuation commands (45) preferably contain the manipulated variables for a closed loop. The controller is preferably implemented in the monitoring unit (40), especially in the data processing unit (42). The manufacturing process is adapted within the nonwoven pre-production plant (10) on the basis of the suitable actuation commands (45) such that the properties of the nonwoven pre-product (3) will change in the desired manner. The actuation commands (45) may also be used in another embodiment for a control in an open loop or for an anticipatory control.

[0081] The actuation commands (45) are transmitted in this preferred embodiment to the plant control unit (11). The plant control unit (11) may be used for the general control and monitoring of the entire nonwoven fabrication plant (15). It is configured, in particular, to process actuation commands (45) for the monitoring, especially the regulation, of the properties of the nonwoven pre-product (3). The plant control unit (11) may comprise especially driver stages in order to transform signal currents of the actuation commands (45) into power currents. As an alternative, the driver stages may also be arranged at another part of the nonwoven pre-production plant (10), especially at a fiber processing device (20) or at a web forming device (30). The central plant control unit (11) may communicate with different parts of the nonwoven pre-production plant (10), especially with the monitoring unit (40), especially via a bus network.

[0082] To generate suitable actuation commands (45), the monitoring unit (40) may process additional information of the nonwoven fabrication plant (10) in addition to the detection results of the detection unit (41). In particular, desired properties of the nonwoven pre-product (3) can be obtained or entered by a user. The monitoring unit (40) is configured to determine deviations between the detected properties and desired properties of the nonwoven pre-product (3). Desired properties may be present in fixed or variable values or value ranges. For example, the desired moisture content of the nonwoven pre-product may be predefined with a value range between a minimum moisture content and a maximum moisture content. Both the detected properties and the desired properties may be in the form of determined values and/or as statistical values. Properties of the nonwoven pre-product (3) may also be present as three-dimensional distributions and/or distributions over time.

[0083] A regulation of the properties of the nonwoven pre-product (3) to predefined desired properties is especially advantageous for reaching a high quality of the finished nonwoven fabric (7). A high-quality nonwoven pre-product (3) is advantageous for the further processing. Certain properties of the web, especially the fiber opening degree or the fiber orientation, are determined during an early phase of the production process, especially of fiber processing devices (20) and web forming devices (30). An early detection of these properties along the production direction (4) improves the possibilities of regulation. Furthermore, certain properties can be better detected before a first web structure-changing further processing. In particular, measuring methods, in which radiation that passes through the web is measured, can yield better information on properties of the web in case of thin and unbonded web. Arrangement of the detection zone (5) along the production direction (4) in front of a first cross lapper (91) and/or a needling machine is therefore advantageous. Short web run times between web formation and the detection zone (5) lead, in addition, to better control dynamics.

[0084] The economy of the plant can also be improved by an automated setting of a nonwoven pre-production plant (10) on the basis of the detection results of the monitoring unit (40). Set-up times can be shortened and the amount of rejects can be reduced.

[0085] FIG. 2 shows another embodiment of a nonwoven pre-production plant (10). The monitoring unit (40) generates actuation commands (45) and transmits these directly to a fiber processing device (20) and/or to a web forming device (30). The web forming device (30) preferably comprises a card (32) and a feeder (31). The feeder (31) feeds pre-processed fibers (2) to the card (32). A continuous fiber stream, which can be processed into a web in a card, is formed in the feeder (31), especially from the pre-processed fibers (2). The feeder (31) has guiding and conveying devices for the fibers, with which the fiber stream can be influenced. For example, the cross section of the feed shaft in the feeder (31) can be changed. An actuating unit (50) adjusts the fiber guiding devices corresponding to actuation commands (45).

[0086] The actuating unit (50) may comprise a driver stage and actuators, especially an electric motor. Actuating units (50) are preferably arranged at a fiber processing device (20) or at a web forming device (30). The actuating units (50) may have a uniform interface for receiving actuation commands (45). The interface may be compatible with a bus system of the web-forming plant (10) and communicate with this. Instead of an actuator of its own, the actuating unit (50) may also have a special machine interface, via which the actuator mechanism of the nonwoven pre-production plant is actuated. The actuating unit (50) may be used as a standardized interface for actuation commands (45) to different actuators. This is advantageous above all if the nonwoven pre-production plant comprises machines of different manufacturers.

[0087] The monitoring process may be supplied as a retrofitting component for existing nonwoven fabrication plants. The use of standardized interfaces at the actuating units (50) for the transmission of actuation commands (45) is especially advantageous in this case because only the actuating units need to be adapted to existing machines.

[0088] FIG. 3 shows a nonwoven pre-production plant (10) with a special fiber processing device (20). Different fiber types (1) are processed in this plant into a web. The fiber processing device (20) comprises a fiber-mixing device (22), in which the different fiber types (1) are blended.

[0089] The fiber blending device (22) is preferably configured to be able to be set with actuation commands (45). This is especially advantageous and to change or to regulate the detected fiber-blending conditions of the nonwoven pre-product (3).

[0090] The fibers (1) are usually fed to the plant in the form of pressed bales. The embodiment shown has bale openers (21), in which the fibers are released from the bales. Fiber bales or lumps of fibers are opened in one or more steps. The fiber processing device (20) may have one or more bale openers (21) and/or fiber opening devices (23). The fibers (1) can be processed with this fiber processing device (20) such that a web can be formed from the fibers (1) in a web forming device (30), especially in a mechanical or aerodynamic card (32). The web forming device (30) may also comprise (additional) fiber opening devices, especially fine openers for multistep fiber-opening processes.

[0091] Both the bale openers (21) and the fiber opening devices (23) are adjustable. The fiber processing process can be set on the basis of the actuation commands (45). This is especially advantageous in the case of a regulation of the detected fiber opening degree of the nonwoven pre-product (3).

[0092] The fiber processing plant (20) may comprise, in addition, a moistening unit (24) (also called lubricating station). Fibers can be wetted or sprayed in a lubricating station with different chemical agents, especially with liquids. For example, an antistatic can be sprayed there onto the fibers in order to prevent or reduce the static charge thereof. Other chemical treatments are also possible. The moistening unit can likewise be set. In particular, the moisture of the fibers can be influenced by setting a moistening unit.

[0093] FIG. 4 shows a top view of a nonwoven pre-product (3) between a web forming device (30) and a web processing device (90). Properties of the nonwoven pre-product (3) are detected in a detection zone (5) by means of a monitoring unit (40). The figure shows a preferred embodiment of a detection unit (41) with a movable sensor (410). Likewise suggested is an embodiment with a sensor beam (411), which extends over the width of the nonwoven pre-product.

[0094] The nonwoven pre-product (3) is delivered continuously in the production direction (4). The detection zone (5) on the formed fabric web (3) is shifted by the conveying motion of the formed fabric web (3) and the movement of the sensor (410). A trajectory (5) of locations at which the properties of the nonwoven pre-product are detected is obtained. Measurements are carried out in the course of time in a zigzag or wave pattern, especially over the entire width of the formed fabric web (3).

[0095] A profile (6) of the properties can be determined from the detected properties, especially over the width of the nonwoven pre-product (3) across the production direction (4). The profile describes the distribution of the properties of the nonwoven pre-product.

[0096] A detected property is preferably provided at a detection location (5i) with location information and/or with time information.

[0097] An automated setting can be carried out by the detection of the properties and/of or a three-dimensional or two-dimensional distribution of the properties at an actuating unit (50) of a web forming device (30) (e.g., a card or a feed shaft) or of a fiber processing device (20).

[0098] A setting is preferably carried out at an actuating unit (50), which is configured to locally influence the properties of the nonwoven pre-product (3). The feed shaft of a feeder (31) is set in the embodiment shown. The feed shaft preferably has actuating units, which are configured to adjust the fiber stream over the entire width and/or at individual locations along the width of the nonwoven pre-product. The weight per unit area of the nonwoven pre-product can be controlled or regulated by the setting of the feed shaft locally and/or two-dimensionally and/or globally.

[0099] As an alternative or in addition, additional actuating units (50), for example, a bale opener, the fitting of a card (32), a dispensing device or a fiber opener, may be set in an automated manner at a fiber processing plant (20) or a web forming device (30).

[0100] The detection zone (5) is preferably arranged following a first card (32). In another embodiment, the detection zone (5) is arranged in the production direction (4) after a second, third or additional card (32) or other web forming device (30). The nonwoven pre-product (3) may be located in certain applications between a plurality of web-forming steps (e.g., cards). The nonwoven pre-product (3) in the detection zone (5) is a laid and unbonded fiber web in this embodiment. The structure-changing further processing may pertain to one or more properties of the nonwoven pre-product.

[0101] The detection zone (5) is preferably arranged in the production direction (4) behind the last card (32). The detection zone (5) is preferably arranged in front of a first bonding device. The cohesion between the fibers of the nonwoven pre-product is increased during the bonding.

[0102] The nonwoven pre-product may consist of a single-layer or multilayer fiber web. The fiber web may be laid especially one on top another within the framework of the web-forming process. The thickness of the fiber web can thus be increased.

[0103] FIG. 5 shows a schematic view of a nonwoven pre-production plant (10) with different embodiments of a monitoring process, especially for the moisture content and/or for the electrical charge.

[0104] The figure shows a possible embodiment of an air-conditioned zone (13). A web forming device (30) (e.g., a card (32)) comprises an air conditioning system (12). The air conditioning system (12) is configured to set the ambient conditions, especially the absolute or relative humidity of the air and/or the temperature, in an air-conditioned zone (13). The air-conditioned zone is integrated in the card (32) in this advantageous embodiment. The housing of the card is essentially separated from the surrounding area in terms of climate control.

[0105] The nonwoven fabrication plant may comprise one or more air-conditioned zones (13) or air conditioning systems (12). The air-conditioned zone (13) may also be built (e.g., for retrofitting) around a machine.

[0106] The nonwoven pre-production plant (10) may comprise one or more moistening devices (24). The moistening device (also called lubricating station) is configured to apply a liquid or a grease to fibers. The moistening device (24) may comprise especially a spray nozzle or other moistening devices. Distilled water is preferably sprayed on. A mist may also be formed. As an alternative or in addition, a chemical, an additive or a lubricant may be applied in a moistening station (24). A moistening device (24) may be combined with an air conditioning system (12). The moistening device preferably comprises one or more liquid tanks and/or controllable pumps. The air conditioning system (12) may comprise, as an alternative or in addition, drying devices (e.g., an infrared lamp, blower or heater).

[0107] The moistening device (24) may especially be integrated into a machine, a fiber processing device (20) or a web forming device (30).

[0108] An air conditioning system (12) and/or a moistening device (24) comprise an actuating unit (50). The actuating unit (50) is configured to receive actuation commands (45). In addition, the actuating unit (50) is configured to set the amount of moisture introduced (e.g., by dispensing a liquid) and/or the removal of moisture (e.g., by setting the temperature or radiation).

[0109] The figure shows a plurality of possible arrangements of a detection zone (5) and of a detection unit (41). In particular, the properties of a fiber stream can be detected behind, in or at a bale opener (21), at a fiber blending device (22) or at another fiber processing device (20). The properties are preferably detected in a detection zone (5) that is arranged in the production direction (4) behind an actuating unit (50). The properties can advantageously be regulated in a feedback control due to such an arrangement. As an alternative or in addition, the properties may also be controlled.

[0110] The detected properties of the nonwoven pre-product may also be used for other purposes, for example, for predictive maintenance and/or damage detection. In an advantageous embodiment, the detected properties are analyzed in an automated manner. The frequency characteristic of the properties is preferably analyzed. In particular, a Fourier transformation may be applied to the detected properties. The frequencies of the detected properties can be compared with frequencies of periodic movements (e.g., speeds of rotating or oscillating parts) or of already known machine parameters. Damage to a component is detected in a preferred embodiment by frequency patterns in the detected properties. An automated warning about a conspicuous frequency characteristic can be generated. In particular, a warning can be generated about a damage or need for maintenance of a certain component.

[0111] The nonwoven pre-product is a flat and/or web-shaped fiber web. The width of the nonwoven pre-product preferably equals 1 m to 4 m.

[0112] The monitoring unit preferably comprises an infrared sensor. As an alternative or in addition, radioactive radiation sensors or X-ray sensors may be used. In particular, isotope backscatter sensors are suitable as well. Radioactive radiation of a krypton isotope is especially suitable for the detection of the properties of a nonwoven pre-product.

[0113] The use of radioactive radiation requires special radiation safety measures. The sensors or the radiation source must, as a rule, be replaced after the end of the half-life. Infrared sensors have the advantage that they can also detect moisture. In addition, the maintenance of infrared sensors is less expensive. Depending on the nonwoven product, different sensors may be advantageous. The special detection zone and the use of the detection results are advantageous in combination with different types of sensors.

[0114] In a preferred embodiment, the monitoring unit (40) is configured with the detection unit (41) and with a data processing unit (42) of its own. This embodiment has the advantage that the monitoring process can be used by retrofitting existing plants with a monitoring unit (40). The product quality is be improved hereby in existing plants as well.

[0115] In another embodiment, the monitoring unit (40) may be configured as a distributed system. In particular, the detection unit (41), the data processing unit (42) and the actuating unit (50) may be configured in separate hardware units. The data processing unit may be implemented, in particular, in a plant control unit.

[0116] Various variants of the present invention are possible. In particular, the features shown, and described in connection with the respective exemplary embodiments may be combined with one another, replaced with one another, supplemented or omitted as desired.

[0117] The disclosure comprises as an independent aspect, which can be used in itself or in combination with the aspect towards which the independent claims are directed, a monitoring process having the following features.

[0118] Monitoring process for a production process of a nonwoven fabric (7) from fibers (1, 2) in a nonwoven fabrication plant (15), characterized in that the moisture and/or the electrical charge of the fibers (1, 2) or of a nonwoven pre-product (3) is detected with a detection unit (41) in a detection zone (5) and the detection results are processed in a data processing unit (42), wherein an actuation command (45) is generated for at least one actuating unit (50) of the nonwoven fabrication plant (15),wherein the actuating unit (50) is configured to set the moisture content of the fibers (1, 2) and/or the moisture content of the nonwoven pre-product (3) and/or the ambient conditions in at least one part of the nonwoven pre-production plant (10).

[0119] Monitoring process, wherein the fibers (1, 2) are moistened with an adjustable moistening device (24), especially by applying a liquid.

[0120] Monitoring process, wherein the moistening device (24) is arranged in the production direction (4) in front of a web forming device (30), especially a card (32).

[0121] Monitoring process, wherein a moistening device (24) for moistening fibers (1, 2) is integrated into a fiber processing device (20), especially a bale opener (21), a fiber opening device (23) or a fiber blending device (22).

[0122] Monitoring process, wherein a moistening device (24) for moistening fibers (1, 2) is integrated into a web forming device (30).

[0123] Monitoring process, wherein the nonwoven pre-production plant (10) comprises at least one adjustable air conditioning system (12).

[0124] Monitoring process, wherein the ambient conditions, especially the humidity of the air and/or the temperature, can be set in a fiber processing device (20) and/or in a web forming device (30) by means of an air conditioning system (12).

[0125] Monitoring process, wherein the nonwoven pre-production plant (10) comprises at least one air-conditioned zone (13) essentially separated from the surrounding area.

[0126] Monitoring process, wherein the air-conditioned zone (13) is limited in space to a fiber processing device (20) or to a web forming device (30), especially to a card (32).

[0127] Monitoring process, wherein the nonwoven pre-production plant (10) comprises an air conditioning system (12) or a moistening unit (24), which can be actuated via an actuation command (45).

[0128] Monitoring process, wherein the moisture content and/or the electrical charge of the fibers (1, 2) or of the nonwoven pre-product (3) are regulated.

[0129] Monitoring process, wherein the moisture content of a part of the fibers (1, 2) or of a local area of the nonwoven pre-product (3) can be set.

[0130] Monitoring process, wherein the nonwoven pre-production plant (10) comprises a moistening unit (24), which is configured to apply liquid in an adjustable actuation zone (46).

[0131] Monitoring process, wherein the actuation zone (46) extends over a part of the fibers.

[0132] Monitoring unit (40) for a nonwoven fabrication plant (15), with a detection unit (41) for detecting the moisture and/or the electrostatic charge of fibers (1) or of a nonwoven pre-product (3), wherein the monitoring unit(40) is configured to carry out a monitoring process in accordance with this disclosure.

[0133] Nonwoven pre-production plant (10) with a monitoring unit, wherein the nonwoven pre-production plant (10) is configured to carry out a monitoring process with at least some of the process features as disclosed herein.

[0134] While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.