MONITORING PROCESS FOR NONWOVEN FABRICATION PLANTS

Abstract

A monitoring process is provided for a method for producing a nonwoven fabric (7) made of fibers (1, 2) in a nonwoven fabrication plant (15). Humidity and/or the electric charge of the fibers (1, 2) or a nonwoven pre-product (3) is detected by a detection unit (41) in a detection zone (5) and the detection results are processed in a data processing unit (42). An actuation command (45) is generated for at least one actuation unit (50) of the nonwoven fabrication plant (15). The actuation unit (50) is configured to set the humidity of the fibers (1, 2) and/or the humidity of the nonwoven pre-product (3) and/or the ambient conditions in at least one portion of the nonwoven pre-production plant (10).

Claims

1. A monitoring process for a process of producing a nonwoven fabric from fibers in a nonwoven fabrication plant, the monitoring process comprising: detecting moisture content and/or the electrical charge of the fibers or of a nonwoven pre-product is with a detection unit in a detection zone; processing detection results in a data processing unit; generating an actuation command for at least one actuating unit of the nonwoven fabrication plant; and (15), wherein the actuating unit is configured to set a moisture content of the fibers and/or a moisture content of the nonwoven pre-product, and/or ambient conditions in at least one part of the nonwoven pre-production plant, wherein the fibers are moistened in a settable moistening unit.

2. A monitoring process in accordance with claim 1, wherein the fibers are moistened in the settable moistening unit by applying a liquid.

3. A monitoring process in accordance with claim 2, wherein the moistening unit is arranged in a production direction in front of a web forming device, comprising a card.

4. A monitoring process in accordance with claim 1, wherein the moistening unit for moistening fibers is integrated into a fiber processing device, comprising a bale opener, a fiber opening device or a fiber blending device.

5. A monitoring process in accordance with claim 1, wherein the moistening unit for moistening fibers is integrated into a web forming device.

6. A monitoring process in accordance with claim 1, wherein the nonwoven pre-production plant comprises at least one settable air conditioning system.

7. A monitoring process in accordance with claim 1, wherein the ambient conditions, comprising humidity of the air and/or temperature, can be set in a fiber processing device and/or in a web forming device by means of an air conditioning system.

8. A monitoring process in accordance with claim 7, wherein the nonwoven pre-production plant comprises at least one air-conditioned zone essentially separated from the surrounding area.

9. A monitoring process in accordance with claim 8, wherein the air-conditioned zone is limited in space to a fiber processing device or to a web forming device, especially to a card.

10. A monitoring process in accordance with claim 1, wherein the nonwoven pre-production plant comprises an air conditioning system or a moistening unit, which can be actuated via an actuation command.

11. A monitoring process in accordance with claim 1, wherein the moisture content and/or the electrical change of the fibers or of the nonwoven pre-product are regulated.

12. A monitoring process in accordance with claim 1, wherein the moisture content of a part of the fibers or of a local area of the non-woven pre-product can be set.

13. A monitoring process in accordance with claim 1, wherein the nonwoven pre-production plant comprises a moistening unit, which is configured to apply liquid in a settable actuation zone.

14. A monitoring process in accordance with claim 13, wherein the actuation zone extends only over a part of the fibers.

15. A monitoring unit for a nonwoven fabrication plant, the monitoring unit comprising: a detection device for detecting the moisture content and/or the electrostatic charge of fibers (1) or of a nonwoven pre-product, a processing unit cooperating with the detection device and configured to carry out a monitoring process comprising: processing detection results in the data processing unit; and generating an actuation command for at least one actuating unit of the nonwoven fabrication plant, wherein the actuating unit is configured to set a moisture content of the fibers and/or a moisture content of the nonwoven pre-product and/or ambient conditions in at least one part of the nonwoven pre-production plant, wherein the fibers are moistened in a settable moistening unit.

16. A nonwoven pre-production plant comprising: at least one nonwoven fabrication plant actuating unit; and a nonwoven fabrication plant monitoring unit comprising: a detection device for detecting the moisture content and/or the electrostatic charge of fibers or of a nonwoven pre-product; and a processing unit cooperating with the detection device and configured to carry out a monitoring process comprising: processing detection results in the data processing unit; and generating an actuation command for the at least one nonwoven fabrication plant actuating unit, wherein the nonwoven fabrication plant actuating unit is configured to set a moisture content of the fibers and/or a moisture content of the nonwoven pre-product and/or ambient conditions in at least one part of the nonwoven pre-production plant, wherein the fibers are moistened in a settable moistening unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0065] In the drawings:

[0066] 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;

[0067] FIG. 2 is a schematic view of a nonwoven pre-production plant with a feeder, with a card and with an actuating unit;

[0068] 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;

[0069] FIG. 4 is a schematic top view of a nonwoven pre-product between a web forming device and a web processing device; and

[0070] 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

[0071] 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.

[0072] 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).

[0073] 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.

[0074] 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).

[0075] 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).

[0076] 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).

[0077] 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).

[0078] 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.

[0079] 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.

[0080] 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 being claimed. 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 claimed.

[0081] 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.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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.

[0086] 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).

[0087] 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.

[0088] 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.

[0089] 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.

[0090] 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).

[0091] 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 fiber are released from the bales. Fiber lumps 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 them 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.

[0092] 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).

[0093] 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.

[0094] 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.

[0095] 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).

[0096] 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.

[0097] A detected property is preferably provided at a detection location (5i) with location information and/or with time information.

[0098] 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).

[0099] 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.

[0100] 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).

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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).

[0108] The moistening device (24) may especially be integrated into a machine, a fiber processing device (20) or a web forming device (30).

[0109] 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).

[0110] 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.

[0111] 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.

[0112] 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.

[0113] 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 can are suitable as well. Radioactive radiation of a krypton isotope is especially suitable for the detection of the properties of a nonwoven pre-product.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] Various variants of the present invention are possible. In particular, the features shown, described or claimed in connection with the respective exemplary embodiments may be combined with one another, replaced with one another, supplemented or omitted as desired.

[0118] 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.

[0119] A monitoring process for a production process of a nonwoven pre-product is characterized in that the properties of a nonwoven pre-product (3), especially the weight per unit area, fiber blending ratio and/or fiber opening degree, are detected with 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) is still an unprocessed fiber web in the detection zone (5) and the properties of the nonwoven pre-product (3) are detected over the width of the nonwoven pre-product (3) across the production direction (4).

[0120] A monitoring process is characterized in that the detection zone (5) is located directly at or close to the discharge of the nonwoven pre-product (3) from a web-forming device (30), especially a card, airlay or spunbond machine.

[0121] A monitoring process is characterized in that the detection zone (5) is located in the production direction (4) in front of a web structure-changing processing device (90), especially a cross lapper (91) or a bonding device (92).

[0122] A monitoring process is characterized in that the nonwoven pre-product (3) is unlaid and/or unbonded.

[0123] A monitoring process is characterized in that the nonwoven pre-product (3) is a single-layer or multilayer fiber web.

[0124] A monitoring process is characterized in that the three-dimensional distribution of properties of the nonwoven pre-product (3) is detected along and/or across the production direction (4), especially with a movable sensor (410) or with a stationary sensor beam (411).

[0125] A monitoring process is characterized in that local properties of the nonwoven pre-product (3) are detected at at least one local detection location (5i), especially with location information.

[0126] A monitoring process is characterized in that the detection results are stored in a memory of the data processing unit (42) and/or are displayed on a display device.

[0127] A monitoring process is characterized in that a frequency analysis of the detection results is carried out, especially on the basis of a Fourier transformation.

[0128] A monitoring process is characterized in that a damage to or a need for maintenance of a component of the nonwoven pre-production plant (10) is determined on the basis of the frequency analysis, especially by comparing a periodic movement of the component and the frequency analysis of the detection results.

[0129] A monitoring process is characterized in that the detection results are compared with desired properties of the nonwoven pre-product (3) and deviations of properties are determined.

[0130] Monitoring process are characterized in that actuation commands (45) are generated for a nonwoven pre-production plant (10), especially a fiber processing device (20) and/or a web forming device (30).

[0131] A monitoring process is characterized in that actuation commands (45) are generated, which are configured to influence and/or to set and/or to regulate properties of the nonwoven pre-product (3) locally in an actuation zone (46), especially in a partial area of the width of the nonwoven pre-product (3) across the production direction.

[0132] A monitoring process is characterized in that a property of the nonwoven pre-product (3), especially a local property or the three-dimensional and/or two-dimensional distribution of a property across and/or along the production direction (4), is regulated or controlled.

[0133] A monitoring process is characterized in that actuation commands (45) are transmitted to a central plant control unit (11), to an actuating unit (50), to a fiber processing device (20) or to a web forming device (30).

[0134] A monitoring process is characterized in that a process parameter, especially a fiber volume flow, the velocity of a fiber conveying device, the position of a fiber guiding device, or the air conditioning, is changed at the nonwoven pre-production plant (10), especially at a fiber processing device (20) and/or at a web forming device (30).

[0135] A monitoring process is characterized in that a detected property of the nonwoven pre-product (3) is influenced in a specific manner by changing a process parameter, especially in order to compensate deviations of properties.

[0136] A monitoring process is characterized in that the weight per unit area of the nonwoven pre-product (3), especially the distribution of the weight per unit area, is detected over the width of the nonwoven pre-product (3).

[0137] A monitoring process is characterized in that the weight per unit area, especially the three-dimensional and/or two-dimensional distribution along and/or across the production direction (4), of the nonwoven pre-product (3), is influenced in a specific manner by setting the fiber conveying speed of the nonwoven pre-production plant (10), the feed characteristic of a feeder (31) or the inlet of a web forming device (30).

[0138] A monitoring process is characterized in that the fiber orientation in the nonwoven pre-product (3) is influenced in a specific manner by setting a web forming device (30), especially a card or aerodynamic card (airlay).

[0139] A monitoring process is characterized in that the blending ratio of the fiber components in the nonwoven pre-product (3) is set in a specific manner by setting a bale opener (21), a dispensing device, a fiber opening device (23) or a fiber blending device (22).

[0140] A monitoring process is characterized in that the opening degree of the fibers in the nonwoven pre-product (3) is influenced in a specific manner by setting a fiber opening device (23) or a web forming device (30).

[0141] A monitoring process is characterized in that the temperature in the nonwoven pre-product (3) is influenced in a specific manner by setting a nonwoven pre-production plant (10), especially a spunbond device or an air conditioning system.

[0142] A monitoring unit (40) for a nonwoven fabrication plant is characterized in that the monitoring unit (40) has a detection unit (41) for detecting properties of a nonwoven pre-product (3) in a detection zone (5) as well as a data processing device (42), wherein the detection unit (41) comprises one or more sensors (410), especially an infrared sensor, radioactive radiation sensor and/or X-ray sensor, wherein the detection unit (41) is configured to detect properties of an unprocessed nonwoven pre-product (3) over the width of the nonwoven pre-product (3) across the production direction (4).

[0143] A monitoring unit (40) is characterized in that the monitoring unit (40) is configured to detect properties of a nonwoven pre-product (3), especially of a loose and/or unlaid and/or unbonded fiber web.

[0144] A monitoring unit (40) is characterized in that the monitoring unit (40) is configured to detect properties of the web in a detection zone (5) directly at or close to the discharge of the nonwoven pre-product (3) from a web forming device (30), especially from a mechanical or aerodynamic card.

[0145] A monitoring unit (40) is characterized in that the monitoring unit (40) is configured to detect the properties of the nonwoven pre-product (3) in a detection zone (5), which is located within or at a web forming device (30), especially at a card (32).

[0146] A monitoring unit (40) is characterized in that the monitoring unit (40) is configured to detect properties of the web in a detection zone (5) in the production direction (4) in front of a first web structure-changing processing device (90), especially a first cross lapper (91) and/or a first bonding machine (92) along the production direction.

[0147] A monitoring unit (40) is characterized in that a sensor (410) of the detection unit (41) is movable along and/or across the production direction (4) over the nonwoven pre-product (3).

[0148] A monitoring unit (40) is characterized in that the monitoring unit (40) is configured to carry out a monitoring process in accordance with one of the above claims.

[0149] A monitoring unit (40) is characterized in that the monitoring unit (40) is configured to generate actuation commands (45) for a nonwoven pre-production plant (10), especially a fiber processing device (20) and/or a web forming device (30).

[0150] A nonwoven pre-production plant (10) with a fiber processing device (20) and with a web forming device (30) for forming a nonwoven pre-product (3) is characterized in that the nonwoven pre-production plant (10) comprises a monitoring unit (40) in accordance with aspects of the above disclosure and is configured to carry out a monitoring process in accordance with aspects of the above disclosure.

[0151] A nonwoven pre-production plant (10) is characterized in that a fiber processing device (20) and/or a web forming device (30) can be set by the monitoring unit (40) in order to influence, especially to regulate, properties of a nonwoven pre-product (3).

[0152] A nonwoven fabrication plant (15) for producing a nonwoven fabric (7) is characterized in that the nonwoven fabrication plant (15) has a nonwoven pre-production plant (10) in accordance with one of the above claims as well as one or more web structure-changing processing devices (90), especially a cross lapper (91) and/or a web bonding device (92), wherein the detection zone (5) of the detection unit (41) is located between the nonwoven pre-production plant (10) and a processing device (90).

[0153] 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.