U.S. patent application number 16/763486 was filed with the patent office on 2020-09-24 for monitoring process for nonwoven fabrication plants.
The applicant listed for this patent is AUTEFA SOLUTIONS GERMANY GMBH. Invention is credited to Eberhard HABERLE, Andreas MEIER.
Application Number | 20200299870 16/763486 |
Document ID | / |
Family ID | 1000004903477 |
Filed Date | 2020-09-24 |
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United States Patent
Application |
20200299870 |
Kind Code |
A1 |
HABERLE; Eberhard ; et
al. |
September 24, 2020 |
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).
Inventors: |
HABERLE; Eberhard;
(Wildberg, DE) ; MEIER; Andreas; (Affing,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
AUTEFA SOLUTIONS GERMANY GMBH |
Friedberg |
|
DE |
|
|
Family ID: |
1000004903477 |
Appl. No.: |
16/763486 |
Filed: |
November 14, 2018 |
PCT Filed: |
November 14, 2018 |
PCT NO: |
PCT/EP2018/081189 |
371 Date: |
May 12, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
D01G 31/003 20130101;
D01H 13/32 20130101; D04H 1/74 20130101; D01H 13/304 20130101; D01G
31/006 20130101 |
International
Class: |
D01G 31/00 20060101
D01G031/00; D01H 13/32 20060101 D01H013/32 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 14, 2017 |
DE |
10 2017 126 753.0 |
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
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a United States National Phase
Application of International Application, PCT/EP2018/081189 filed
Nov. 14, 2018, and claims the benefit of priority under 35 U.S.C.
.sctn. 119 of German Application 10 2017 126 753.0, filed Nov. 14,
2017, the entire contents of which are incorporated herein by
reference.
TECHNICAL FIELD
[0002] The present invention pertains to a monitoring process for
nonwoven fabrication plants.
TECHNICAL BACKGROUND
[0003] Nonwoven fabrics from different types of fibers and fiber
blends are used in many different areas (e.g., hygiene articles,
automobile trims, packaging materials or building materials).
[0004] Synthetic fibers are preferably used as raw materials.
Recycled fibers, i.e., fibers from synthetic or carbon materials,
are processed nowadays into nonwoven fabrics as well.
[0005] The manufacture of nonwoven fabrics, i.e., finished nonwoven
products, is carried out, in general, in a plurality of steps.
Fibers are at first released and processed usually from pressed
bales in fiber processing devices. Different types of fibers are
possibly blended into a fiber blend. A still rather loose fiber
web, a so-called nonwoven pre-product, is formed from the processed
fibers. Web forming devices, especially mechanical or aerodynamic
cards, are used for this. This nonwoven pre-product does not yet
have the desired structure, especially thickness or strength, of
the finished nonwoven fabric. The nonwoven pre-product is processed
in further steps to produce the finished fabric. The structure of
the fiber web formed previously is changed during the further
processing, e.g., in a cross lapper or in a needling machine.
Depending on the application, the nonwoven pre-product is processed
in different numbers of processing steps and processes to form the
finished nonwoven fabric.
[0006] Nonwoven fabrication plants, in which measurements are
carried out on the finished nonwoven fabric at the end of the
production plant or after a bonding machine, are known from
practice.
SUMMARY
[0007] An object of the present invention is to show an improved
monitoring process for nonwoven fabrication plants. The present
invention accomplishes the object with the features described in
the independent claims.
[0008] The disclosure covers a monitoring process, which comprises
both the monitoring process and suitable devices. The disclosure
covers, in particular, a nonwoven pre-production plant as well as a
monitoring unit.
[0009] The combinations of prior-art processing steps and
processing machines are many and diverse. The monitoring process
being disclosed is especially suitable for use in different
configurations of plants. Depending on the application, certain
requirements are imposed on the quality of the finished nonwoven
product. These requirements may pertain to the thickness,
composition, structure, feel, color or load-bearing capacity of the
nonwoven product.
[0010] There are many possible settings and process parameters
along the multistep fabrication process of a nonwoven product,
which affect the quality of the end product. It is especially
advantageous to carry out the settings of the machine, especially
in the early steps of fabrication, in an automated manner. The
settings may be carried out once and/or continuously during the
production at the start of a production run (set-up time).
[0011] The nonwoven pre-production plant may be a part of a larger
nonwoven fabrication plant. The nonwoven pre-production plant
processes fibers into a nonwoven pre-product. It represents a first
process phase within the larger nonwoven fabrication plant. A
nonwoven pre-production plant may comprise especially one or more
fiber processing devices and one or more web forming devices, e.g.,
a card. The entire nonwoven fabrication plant processes fibers into
the finished nonwoven fabric. The nonwoven pre-product is an
intermediate product of the entire nonwoven production process.
[0012] The monitoring unit may be a part of a nonwoven
pre-production plant. The nonwoven pre-product can be processed
further into a nonwoven fabric in downstream processing
machines.
[0013] A first essential aspect of the present invention pertains
to the detection of properties of an unprocessed nonwoven
pre-product.
[0014] An unprocessed fiber web, the nonwoven pre-product, is
produced in the nonwoven pre-production plant. This first phase of
the process is also called web formation. The production of the
nonwoven pre-product, i.e., of the unprocessed web, may likewise be
carried out in a plurality of steps. The nonwoven pre-product may
be produced, for example, in a plurality of cards arranged one
after another in order to reach a necessary web thickness for the
further processing.
[0015] The unprocessed web of the nonwoven pre-product still has
poor cohesion between the fibers. The nonwoven pre-product is
unprocessed especially after the web formation (e.g., since the
discharge from a card). The fiber web formed in the web forming
device (nonwoven pre-product) is unchanged in the detection zone. A
change in the structure of the nonwoven pre-product (e.g., due to
bundling, bonding or laying) takes place only after the detection
zone.
[0016] The structure of the nonwoven pre-product is changed
normally following a nonwoven pre-production plant in a web
processing device. The further processing comprises, e.g., a
bonding of the web, also called "bonding." Different mechanical,
thermal and chemical bonding techniques are known in practice. For
example, the web is calendered, needled or bonded with water jets
during the further processing. The structure of the web is changed
(e.g., bonded) such that the desired product properties of the
nonwoven product are obtained.
[0017] One aspect of the present invention is that the properties
of a nonwoven pre-product are already detected in an automated
manner in order to monitor the production process. The detected
properties of the nonwoven pre-product may comprise, e.g., the
weight per unit area, moisture content, fiber orientation, fiber
opening degree, fiber blending ratio, temperature, density and/or
the electrical or electrostatic charge of the fiber web. It is
possible to detect both a plurality of properties or only a certain
selection of properties by measurements.
[0018] The detection of the properties of the nonwoven pre-product
has various advantages. The properties of the nonwoven pre-product
substantially influence the processing in the web processing
devices of the nonwoven fabrication plant. For example, the degree
of opening of the fibers in the nonwoven pre-product may influence
a subsequent bonding. The fiber orientation in the nonwoven
pre-product influences the mechanical load-bearing capacity of the
nonwoven product. It is therefore advantageous to already detect
the properties of the nonwoven pre-product. It is advantageous, in
particular, for optimizing the quality of the finished nonwoven
fabric to detect the properties of the nonwoven pre-product. The
detection of the properties on the nonwoven pre-product is also
advantageous for optimizing the web processing devices of the
nonwoven fabrication plant.
[0019] It is, furthermore, advantageous to detect the properties of
the nonwoven pre-product before it is processed further. Certain
properties can be measured with greater difficulty after a further
processing. In particular, certain measuring methods, e.g.,
measurements with infrared radiation or radioactive radiation, can
be used especially well on the thin fiber web of the nonwoven
pre-product. For example, the irradiation can be measured better on
a thin fiber web than on a nonwoven that had already been subjected
to further processing. Measurements by means of infrared radiation
and/or radioactive radiation on the nonwoven pre-product are
especially advantageous.
[0020] Another essential aspect of the disclosure is the detection
of a property of the nonwoven pre-product over the width thereof.
The nonwoven pre-product is conveyed as a web-shaped fiber web in
the production direction. The three-dimensional or two-dimensional
distribution of the properties along and/or across the production
direction is of particular significance for the quality of the
product. Properties such as the weight per unit area, fiber opening
degree or fiber orientation may show local differences. Local
defects, accumulations of material, lumps or similar effects can be
detected in the three-dimensional or two-dimensional distribution
of the properties.
[0021] The properties are preferably detected over the entire width
of the nonwoven pre-product. The width is defined in the sense of
this disclosure as the extension of a fiber stream or of a nonwoven
pre-product (i.e., of a nonwoven pre-product) at right angles to
the production direction (i.e., conveying direction). The detection
zone preferably extends over the entire working width of a web
forming device (e.g., a card).
[0022] The detection may be carried out by means of a stationary or
movable sensor. The detection is preferably carried out with
constant accuracy over the entire width of the nonwoven
pre-product. An (approximately) continuous distribution of the
properties is advantageously detected. A cross-sectional profile
and/or a curve describing the changes in the properties in the
longitudinal direction can thus be determined.
[0023] In particular, consecutive measurements may be carried out
at a plurality of local detection locations. The local detection
locations may be offset in relation to one another in the
longitudinal and/or transverse directions. The local detection
locations preferably overlap each other. A continuous property
profile can be generated especially from a combination of
overlapping detection locations of constant measuring accuracy.
Location information and/or time information is preferably detected
for each detected property.
[0024] The two-dimensional distribution of a property is preferably
detected. The weight is preferably detected as a weight per unit
area distribution. The three-dimensional distribution of a property
preferably pertains to the area of the nonwoven pre-product. The
three-dimensional distribution is preferably defined as the
two-dimensional distribution of a property parallel to the nonwoven
pre-product. It is especially advantageous for an economical
measuring technique not to detect a third dimension of a property
distribution, especially at right angles to the nonwoven
pre-product. Measuring inaccuracies in the distribution at right
angles to the area of the nonwoven pre-product may lead to great
distortions or noise in the result of the detection.
[0025] The properties of the nonwoven pre-product are already
significant for the production of a high-quality nonwoven fabric.
If the properties of the fiber web formed deviate from the desired
properties, this may lead to production problems during the further
processing of the nonwoven pre-product or to an impairment of the
quality of the end product. For example, the moisture content in
the nonwoven pre-product may affect the further processing in
certain machines. It is therefore advantageous to detect the
properties of the fiber web before a first further processing,
especially if the web structure is changed in the process involved.
Structural changes take place especially during the bonding of a
web.
[0026] Higher requirements on quality can be complied with by
automated actuating actions for regulating or controlling
properties of the nonwoven pre-product.
[0027] The properties of the nonwoven product are checked in
practice, if at all, only at the end of the production process.
Settings for optimizing the quality of the nonwoven product are
made, as a rule, manually by the operator of the machines and they
strongly depend on the experience and qualification of the
particular person. Settings are often made, moreover, only at the
start of a production run. The quality of the product can be
ensured by the automated monitoring independently from the
operating staff.
[0028] Another advantage of the detection of properties of the
nonwoven pre-product is the use of the detection results for an
automated setting of the nonwoven pre-production plant. The
detected properties may be used for a single-time setting during a
retrofitting or a production start. In addition, the properties can
be regulated on the basis of the detection results during the
production process by setting the nonwoven pre-production plant.
The regulation of a fiber processing device and/or of a web forming
device on the basis of the detected properties of the nonwoven
pre-product is especially advantageous. Detection of the properties
close to the discharge of the nonwoven pre-product from a web
forming device is especially advantageous for this.
[0029] The sooner the properties of the nonwoven pre-product are
detected in the production process, the shorter idle times can be
obtained in the regulation or control of the machines. Short idle
times improve the control performance. The amount of rejects can be
reduced by an early detection of deviations in the properties. It
is possible, in particular, to obtain closer quality tolerances for
the finished nonwoven product by detecting the properties of the
unprocessed nonwoven pre-product.
[0030] A contactless measuring technique, e.g., infrared, X-ray or
radioactive radiation, as well as optical measuring methods may be
used for the detection of the properties of the nonwoven
pre-product. One or more sensors or radiation sources may be
arranged above and/or under the fiber web. The sensors may be
arranged stationarily or movably. A combination of stationary and
movable sensors is possible as well. In particular, sensors may be
moved over the width of the nonwoven pre-product at right angles to
the production direction. This is especially advantageous for
detecting a three-dimensional or two-dimensional distribution of
the properties. A sensor beam, which extends over the width of the
nonwoven pre-product, may be used as well.
[0031] The measurements are carried out in a detection zone whose
arrangement within the production plant is especially advantageous.
Measurements may be carried out locally and/or globally at the
nonwoven pre-product. In particular, sensors may carry out local
measurements, e.g., for detecting the moisture content. In
addition, sensors may carry out measurements over a certain area of
the nonwoven pre-product.
[0032] The detection zone for the detection of the properties of
the nonwoven pre-product is preferably located directly at or near
the discharge of the nonwoven pre-product from the web forming
device. This arrangement is advantageous because the detection of
the properties takes place with the shortest possible time shift
relative to the web formation process. Shorter idle times can be
obtained due to the arrangement of the detection zone in the close
proximity of the web forming device especially for the regulation
of a fiber processing or web-forming process on the basis of the
detected properties. The control performance can be improved in
case of a regulation by shorter web run times between the web
formation process and the measurement of the properties.
[0033] Furthermore, it is advantageous to measure the properties of
the fiber web before it is processed in a next step and the
structure of the web is changed in the process. Arrangement of the
detection zone in the production direction in front of a web
processing device, preferably in front of a first cross lapper or a
first bonding device, is especially advantageous. Certain
properties of the nonwoven pre-product, for example, the fiber
orientation or the fiber opening degree, can be better detected in
the unprocessed fiber web. The properties of the nonwoven
pre-product, which are to be detected, may also be changed during
the further processing. The assignment of deviations in properties
to possible causes in the fiber-processing or web-forming processes
is facilitated by this advantageous arrangement of the detection
zone.
[0034] The monitoring process is used to monitor the production
process and the product quality. Depending on use, high quality
requirements may be imposed on the nonwoven fabric. Manufacturers
of nonwoven fabrics have an interest in monitoring the production
process within the framework of quality assurance. It is
particularly advantageous to store and to document detected
properties of the nonwoven pre-product. Causes of deviations in
quality in the nonwoven fabric can thus be better determined.
[0035] An embodiment of the monitoring process for the automated
setting of the nonwoven pre-production plant is especially
advantageous.
[0036] The monitoring unit may be a part of a nonwoven
pre-production plant, which is configured especially to carry out
the monitoring process. Implementation of the monitoring unit in a
production plant with a central plant control unit is especially
advantageous. The monitoring unit may have actuating units
specially configured for the setting and/or regulation of the
nonwoven pre-production plant. These actuating units may have
actuators, with which physical settings can be implemented at a
fiber processing device or a web forming device.
[0037] Another essential aspect of the disclosure is the monitoring
of the moisture content and/or electrostatic charge of the fibers
or of the nonwoven pre-product. This aspect of the present
disclosure is of inventive significance of its own.
[0038] Changing ambient conditions or fluctuating fiber properties
do not have an adverse effect on the product quality due to the
disclosed monitoring process. Deviations in quality can be
prevented or mitigated. The amount of rejects can be reduced by the
monitoring process.
[0039] Materials or components may become charged electrostatically
due to friction. Airborne fibers or adhesion of fibers to
components because of electrostatic fields may be undesired in the
area of the nonwoven industry.
[0040] Electrically charged fibers may readily adhere to machine
parts, e.g., conveyor belts, and interfere with the production
process. Electrostatic charge of the fiber material may develop
especially in the case of electrically non-conducting or only
weakly conducting materials (e.g., plastics).
[0041] Electrical breakdowns with sparking can be prevented by
monitoring the electrical charge.
[0042] The build-up of electrostatic fields is closely linked with
the moisture content of the fiber material and the ambient air.
Electrical charges of the fiber material can be reduced or even
prevented above a certain moisture level. Both the moisture content
of the fibers themselves and of the ambient air play a role
concerning the quality of the production process.
[0043] In addition to electrostatic effects, moisture content may
also have an adverse effect on machine parts. For example,
corrosion may develop on machine parts in case of an excessively
high moisture content. An excessively high moisture content of the
fibers may lead to undesired properties in the nonwoven pre-product
or finished nonwoven product (e.g., lump formation). An excessively
low moisture content may facilitate electrostatic fields.
[0044] It is therefore advantageous for the quality of the product
and the durability of the plant to monitor the moisture content
and/or the electrical charge of the fibers and/or of the nonwoven
pre-product. The moisture content is advantageously maintained in
an optimal range. The relative humidity of the air is preferably
taken into consideration as a function of the ambient
temperature.
[0045] The climatic ambient conditions of a plant may vary
considerably depending on the location in which the plant is used
and the time of the year. Seasonal, climatic and weather-related
differences in the ambient conditions at the production site can be
mitigated by the monitoring process. The humidity of the air and
the ambient temperature can be regulated independently from the
external ambient conditions. Undesired airborne fibers and the
adhesion of fibers can be prevented all over the world.
[0046] The properties of a plurality of fiber streams can be
monitored separately especially in the case of fiber blends from
different fiber types and fiber sources. Fibers are often supplied
as the raw material as pressed bales. Depending on the storage and
transportation conditions, the fibers introduced into the plant may
possess different properties (e.g., moisture contents). An
automated monitoring of the properties of the fibers or of the
nonwoven pre-product may compensate external influencing
factors.
[0047] The moisture content and/or the electrical charge of the
fibers or of a nonwoven pre-product are detected with a detection
unit. The detection unit may comprise one or more sensors. Infrared
sensors are preferably used. The detection unit is arranged in the
nonwoven fabrication plant such that the properties are detected in
a suitable detection zone.
[0048] The detection results are processed for the automated
monitoring in an electronic data processing device. The detection
results represent an important source of data. In the sense of a
digitized production (Industry 4.0), the detection results can be
analyzed for various purposes. For example, the data can be used to
regulate or control the plant. As an alternative or in addition,
the detection results may be used to document the process and for
quality assurance.
[0049] The data may be processed in real time and/or stored
permanently.
[0050] Suitable actuating actions can be carried out at the plant
in an automated manner on the basis of the detected moisture
content or the detected electrical charge. An actuation command is
generated for an actuating unit of the plant, of a machine or of a
component. The actuation command is an electronic signal. The
actuation command may be exchanged especially via a bus system
between data processing units (e.g., the detection unit and a plant
control unit).
[0051] The ambient conditions can advantageously be set in a
certain range of air conditioning of the nonwoven fabrication plant
with an air conditioning system. The air conditioning system is
preferably configured to heat or to cool the ambient air. In
addition, the air may be humidified and/or dried. Moisture can
advantageously be applied directly to the fiber material (e.g., by
spraying, coating or wetting). As an alternative or in addition,
the moisture content can be increased or moisture can be removed
indirectly via the ambient air. The air conditioning system may
advantageously dry fibers or air.
[0052] The combination of direct moistening and indirect air
conditioning is especially advantageous. For example, a liquid can
be sprayed onto fibers by a moistening unit. The fibers can reduce
their electrostatic charge due to the increase in the moisture
content. In addition, the moisture content can be maintained at an
optimal level by means of dry ambient air in an air conditioned
zone (which is, for example, susceptible to corrosion). A specific
moistening of the fibers may be advantageous especially in a phase
of the process in which undesired airborne fibers may occur.
[0053] The air-conditioned zone of the nonwoven fabrication plant
is advantageously limited locally. A separated air-conditioned zone
increases the energy efficiency of the plant, especially compared
to air conditioning of an entire hall.
[0054] The actuation command preferably comprises a set value for
the quantity of a liquid, a temperature preset value or a moisture
preset value. As an alternative or in addition, actuation commands
may comprise set values for mechanical actuating units (e.g., speed
for a drive, angle for a guiding device, position of an actuation
zone, motion specifications).
[0055] The components of the plant have suitable interfaces for
receiving and/or transmitting actuation commands.
[0056] A plurality of detection units or actuating units may
advantageously be used for separate fiber streams (fiber sources).
Differences between the properties of different fiber streams can
be detected and compensated.
[0057] The detection zone may be arranged at different locations in
the nonwoven fabrication plant. Arrangement of a detection zone at
the outlet of a web forming device (e.g., card, airlay, spunbond
device) or of a fiber processing device (e.g., bale opener, fiber
opener, dispensing device, fiber blending device) is advantageous.
A plurality of detection zones, especially with a plurality of
detection units, may be arranged along the production process. For
example, a detection zone may be arranged in a bale opener, after a
fiber blending device and/or at the outlet of a flock feeder.
[0058] In a first embodiment, the monitoring process may be used
for quality assurance purposes. The detected properties of the
nonwoven pre-product are processed in a data processing unit. The
detection results may comprise raw measured data or already
pre-processed property data. Data processing algorithms, with which
the measured data are enriched with time and space information, may
be used when processing the detection results. Furthermore,
patterns can be determined in the time- or space-related changes of
the detection results. The detection results may be stored both in
a memory, especially a suitable data bank for quality assurance
purposes, and displayed on a suitable display device, e.g., a
central terminal of the plant. This processing is advantageous
because undesired properties can be detected during an early phase
of the production process already in the nonwoven pre-product.
[0059] A transverse and/or longitudinal profile of the properties
is preferably generated from the detection results. The
longitudinal profile may contain especially a curve showing the
changes in the properties over time and/or in space along the
production direction. The transverse profile comprises a curve
showing the properties over the width of the nonwoven pre-product
and/or of a fiber stream. Location and/or time information is
preferably stored for a detected property. For example, the
location of a measurement can be stored in running meters in
reference to a reference location (e.g., running meters since the
start of the production). A production time (e.g., date and time)
may also be linked with the detected properties. The linkage of the
detected properties with the detection location is especially
advantageous for an accurate control or regulation of the
properties.
[0060] In another embodiment, the monitoring process can be used
for setting the nonwoven pre-production plant, especially for
regulation purposes. The detected properties can be compared with
desired properties in order to detect deviations in the properties.
Actuation commands are generated for the setting of the nonwoven
pre-production plant by means of suitable decision rules. Both the
detected properties and desired properties as well as determined
deviations in the properties and/or other process parameters are
taken into consideration when generating actuation commands.
[0061] The actuation commands are generated especially for setting
fiber processing devices and/or web forming devices. In particular,
the properties of the nonwoven pre-product can be regulated by
setting the nonwoven pre-production plant. Additional information,
e.g., from other sensors of the pant, may also be taken into
consideration in the regulation. For example, the fiber opening
degree can be measured and regulated by setting one or more fiber
opening devices. Suitable actuation commands are generated and
transmitted either to a plant control unit, directly to a fiber
processing or web forming device or to a suitable actuating
unit.
[0062] Based on the actuation commands, actuators of the nonwoven
pre-production plant can change the fiber processing or web forming
devices such that the detected properties will change in the
desired direction. For example, an actuation command for an
actuating unit may be transmitted at the feed shaft of a flock
feeder. The width of the feed shaft is adjusted corresponding to
the actuation command by means of an actuator, e.g., an electric
motor.
[0063] Suitable control algorithms are used to regulate the
properties of the nonwoven pre-product by setting the nonwoven
pre-production plant. Both simply linear and complex nonlinear
controls may be used to generate the actuation commands. In
particular, trained artificial neural networks or fuzzy controls
may be used for processing the detection results and for generating
suitable actuation commands.
[0064] The various features of novelty which characterize the
invention are pointed out with particularity in the claims annexed
to and forming a part of this disclosure. For a better
understanding of the invention, its operating advantages and
specific objects attained by its uses, reference is made to the
accompanying drawings and descriptive matter in which preferred
embodiments of the invention are illustrated.
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.
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