WO2005015202A1

WO2005015202A1 - Method and device for measuring the strip mass and/or variations in the strip mass of a running fiber assembly and spinning preparation machine equipped with a measuring device

Info

Publication number: WO2005015202A1
Application number: PCT/EP2004/051196
Authority: WO
Inventors: Joachim Dämmig; Chokri Cherif
Original assignee: Rieter Ingolstadt Spinnereimaschinenbau Ag
Priority date: 2003-08-06
Filing date: 2004-06-22
Publication date: 2005-02-17
Also published as: EP1651954A1; CN1833166A; DE10335856A1; WO2005015202A9

Abstract

The invention relates to a method for measuring the strip mass and/or the variations in the strip mass of a running fiber assembly (FV), whereby signals of a number of sensors (11, 12; 31, 32), which record the strip mass or the variations in the strip mass, are processed with at least partially different transmission functions, and at least one defined frequency range is filtered out from the frequencies contained in the measurement signal of at least one sensor, and at least one portion of the filtered signal is used during the processing of signals of at least one other sensor. The invention also relates to a measuring device (1; 3) for measuring the strip mass and/or the variations in the strip mass of a running fiber assembly FV and to a spinning preparation machine equipped with a measuring device (1; 3) of this type.

Description

Description METHOD AND DEVICE FOR MEASURING THE TAPE MEASUREMENT AND / OR THE TAPE MEASUREMENT VARIATIONS OF A RUNNING FIBER ASSEMBLY AND SPINNING PREPARATION MACHINE WITH A MEASURING DEVICE

The present invention relates to a method for measuring the tape mass and / or the tape mass fluctuations of a running fiber structure, in particular on a spirits preparation machine, wherein signals from several sensors with at least partially different transfer functions are processed.

Furthermore, the present invention relates to a device for measuring the tape mass and / or the tape mass fluctuations of a running fiber structure with a measuring transducer and several sensors with at least partially different transmission fiiixions.

Likewise, a spinning preparation machine, in particular a carding machine, draw frame, Kairi machine or a multi-furnace machine, with at least one measuring device for measuring the sliver mass and / or the sliver mass fluctuations of a running fiber assembly, which comprises a transmitter and several sensors with at least partially different transmission functions, is proposed , The machine contains at least one open or closed control loop, which comprises at least one measuring device, a regulating unit and at least one drafting device for stretching a running fiber structure and is designed to regulate band mass warnings of the fiber structure and / or a band monitoring unit, the at least one measuring device and an off - Includes unit of value and is designed to calculate, display and / or store quality data of the current fiber structure.

A multi-stage machine is designed to carry out at least two similar or different types of processed gsscbritten. This can be, for example, a draw frame with several drafting systems or a card with a drafting system. Such a machine can be modular or integrated.

In machines for transporting and / or processing a fiber structure, it is often necessary to measure the strip mass and / or the strip mass fluctuations of the fast-running fiber structure. This applies in particular to spinning preparation machines, such as. B. cards, draw frames or combers. there the measurement results obtained are mainly needed to regulate the work process of the machine in question and / or to obtain quality data of the current fiber structure.

In current measuring devices, the running fiber structure is mechanically scanned, for example with a sensing and grooving roller unit or a spring-loaded sensing element with a fixed counter surface. Due to the inertia of the sensing element, however, it is not possible with such devices to detect short-wave fiber band fluctuations, particularly in the case of fast-running fiber assemblies. The moving mass can be reduced by using a leaf spring as a feeler element, but this also leads to a reduction in the fiber pressure, as a result of which the measurement result strongly depends on further band parameters, such as fiber parallelization or bulkiness. Another disadvantage is the lower mechanical stability.

Measuring devices with sensors without a moving mechanical probe element have a wider bandwidth, but do provide a measurement signal which is strongly dependent on the environmental conditions, for example the temperature or the air humidity, but also on other band parameters, such as for example the fiber parallelization or the fiber moisture , This applies in particular to pneumatic, capacitive, optical, acoustic and radioactive sensors, but also to microwave sensors.

A combination measuring device is known from EP 0 631 136 B1, in which the running fiber structure is examined simultaneously by a mechanical and a pneumatic sensor. It is proposed to use the signal from the pneumatic sensor for belt regulation and the signal from the mechanical sensor for belt monitoring. Furthermore, it is disclosed that by comparing the signals of these different types of measuring systems, other characteristics of the band, such as. B. the fiber length, the bulk, the short fiber portion, the portion of floating fibers and the fiber fineness and parallelism can be determined. However, it is not disclosed how the bandwidth and or the measuring accuracy of the measuring device can be improved by using measuring signals from a plurality of sensors which are based on a different measuring principle.

The object of the present invention is therefore to provide a method and a device for measuring the tape mass and / or the Ban rssswwaijkung a running fiber structure and a spinning preparation machine with a measuring device which avoids the disadvantages mentioned.

The object is achieved by a method, a measuring device and a spinning preparation machine with the features of the independent claims.

In the method according to the invention for measuring the tape mass and / or the Band mass fluctuations of a running fiber structure, which consists of a single band or a combination of several bands, signals from several sensors with at least partially different detection behavior are processed.

[012] Sensors, in particular if they work according to a different measuring principle, differ among other things in the extent to which they are able to record measured variables that change quickly over time. One can then speak of a different dynamic behavior or, briefly, of a different dynamic of the sensors. The dynamics of a sensor can be characterized by its yield function. This describes the amplitude and the phase position of the output signal as a function of the frequency of an input signal.

The sliver mass and / or the sliver mass fluctuation of a running fiber structure is a measurement variable which can vary very quickly over time depending on the running speed of the fiber structure. It is therefore advisable to use several sensors with different dynamics or transfer functions to record this measured variable. In the method according to the invention, at least one defined frequency range is filtered out of the frequencies contained in the measurement signals of at least one sensor for further processing and the fluctuations in mass mass of a wavelength range corresponding to the frequency range are determined. The signals obtained by the filtering are used in the processing of signals from at least one further sensor.

[014] “Use in the processing of signals” should be understood to mean any influence on the parameters or on the use of the signals to be processed in each case.

Filtering can be used to exclude signal components from the further processing which are not required for further processing and which may even be disruptive. This can be, for example, signal components that result from resonance effects. It is also possible to suppress frequency ranges in which the sensor has an unfavorable interference / useful signal ratio. All in all, the filtering provides a signal which maps the band-mass fluctuations of the relevant frequency and thus wavelength range with great accuracy. The signal is therefore ideally suited as a reference signal for other sensors, but also as a partial signal for recording the entire fluctuations in the strip mass.

[016] Furthermore, the limitation of the frequency range enables a sensor to be optimized in such a way that it has a large accuracy works. Especially in the case of mechanical sensors with a movable probe element, it is advantageous to optimize essential parameters, such as, for example, the moving mass or the pressing force on the fiber band, for a specific frequency range. By limiting the frequency range of a sensor, it can also be made simpler in many cases, which then also leads to a corresponding cost saving. Band mass fluctuations of other wavelength ranges can be determined with one or more additional sensors. If necessary, the signals from the other sensors can also be filtered. As a result, the method allows a broadband detection of the band mass fluctuations or the band mass, with high measuring accuracy in the entire frequency range.

It is advantageous here if the signals from a sensor are filtered such that the respective sensor has a transfer function with constant gain or amplitude response in this frequency range. In this way, an output signal is obtained in which the amplitude is independent of the frequency of the input signal, provided that only this frequency is contained in the respective frequency range. If the sensor has a constant phase response in this frequency range, the further processing of the signals is simplified.

[018] The frequency range to be recorded is preferably divided into a number of adjacent intervals. These frequency intervals can be filtered out from the signals of several sensors. A specific sensor can be assigned to each interval, the assignment between the interval and sensor being able to take place on the basis of the transmission behavior of the respective sensor. The respective sensor preferably has a constant ampute transfer function in the respective interval. The frequency range that corresponds to the interval assigned to it can now be filtered out from the signals of the respective sensor. The filtered signals from a plurality of sensors can then be combined, so that an overall signal is obtained which represents the frequency range of interest as a whole. The combination of two signals can be understood to mean the formation of a new signal which comprises at least parts of both original signals. For example, signals can be added.

[019] At least one high pass, one low pass, one band pass and / or one band stop can be used to filter the measurement signals. It is irrelevant here whether the filters are designed in analog or digital technology, since the necessary A / D and / or D / A converters are available at low cost and are technically sophisticated.

It is also advantageous if the signals are filtered in such a way that they are used directly to regulate a work process, such as, for example, the stretching of a fat serbandes in a drafting system, can be used. The signals can also be filtered in such a way that they are immediately suitable for the acquisition of irritated quality data of the fiber structure. By filtering through a tie pass, for example, the strip weight averaged over a longer strip section can be determined directly.

It is particularly advantageous if data for the calibration of a further sensor and / or for the correction of the measurement errors of a further sensor are obtained from the filtered signals of a sensor. The term caution means in particular the adaptation of the sensor core line to a reference characteristic. These characteristics describe the relationship between the input signal and the output signal of a sensor. If the sensor characteristic is shifted parallel with respect to the reference characteristic, the sensor can be calibrated by adding a constant value (offset) to the output signal of the sensor. However, if there is a deviation in the slope of the characteristic curve, that is to say a deviation in the measurement sensitivity, the sensor can be calibrated by varying the gain. The calibration can take place on the sensor itself or in a downstream processing unit, for example in a transmitter or transducer. In the case of non-linear characteristic curves, calibration can also be carried out at intervals.

It is advantageous here to compare measurement signals that were measured in a common frequency range by at least two sensors. This makes it possible to precisely determine both the required offset and the required change in the gain. The calibration can relate, for example, to the zero point and / or to the gain of a sensor.

It is particularly advantageous if the measurement signals of a sensor working according to a mechanical principle, which generally has a low dynamic behavior, for calibration and / or for correcting the measurement errors of a sensor working according to another measurement principle, which preferably has a highly dynamic behavior has to be used. A mechanical sensor is preferred here, which works according to the sensing and grooving principle. This results from the fact that such a sensor, at least in the low-frequency range, supplies very precise absolute values and, moreover, is particularly insensitive to external influences, such as temperature, air humidity or band structure. The measurement fire correction can relate to random and / or systematic measurement errors.

[024] The measurement signals of the sensor operating according to a mechanical principle, preferably with a feeler and grooved roller unit, can also advantageously be used to substitute measurement signals that deviate extraordinarily, according to a other measuring principle working sensor can be used.

As a further sensor, a sensor operating according to a different mechanical principle, a pneumatic, a capacitive, an optical, an acoustic, a radioactive sensor or a microwave sensor can be used.

It is advantageous here if the filtered signals of at least two sensors are combined for the purpose of regulating a work process and / or for recording quality data of the fiber structure. This allows the advantages of different measuring principles to be combined.

[027] It is also useful if a phase difference, for example due to the time difference between the measurement at a specific point in the current fiber structure with one sensor and the measurement of the same location in the fiber structure with another sensor or with the phase changes of the sensors used, transducers , Filter and / or other elements of the arrangement can arise, is balanced. If the phase difference is different at different frequencies, this can be corrected in relation to frequency. The phase difference can be compensated for, for example, with an all-pass, preferably with an all-pass with a controllable phase shift or an intermediate store. The F st-I_j7First-Out principle can be used for a buffer. When a new measurement value is saved, the measurement value of a certain number of measurement values that has been in memory for the longest time is output for further processing and deleted in the memory. The storage and removal process can be cycled depending on the running speed of the fiber structure. In this way it can be ensured that such measured values are combined which relate to the same place on the running fiber structure.

It is particularly advantageous if the first sensor is a narrow-band, in particular a mechanical sensor, and the second sensor is a broad-band, in particular a mechanical sensor with less moving mass than the first sensor, a pneumatic, a capacitive, an optical, an acoustic , a radioactive sensor or a microwave sensor is used.

The term "broadband sensor" can be understood to mean a highly dynamic sensor which is suitable for detecting high-frequency fluctuations in the band mass. A narrowband sensor is a low-dynamic sensor which lacks this property.

With such a configuration, the advantages of sensors working differently can be brought together to effect. Measurements of the tape mass and / or the tape mass fluctuations of a fiber structure can be carried out accurately and broadly. At the same time, the dependence on disturbance variables decreases. Furthermore, the at least partial redundancy results in a high level of confidence. non-negligence of the procedure.

The measuring device according to the invention has a transmitter that filters out a defined frequency range from the measurement signal of at least one sensor in order to detect band mass fluctuations of a specific wavelength range. With a known speed v of the fiber sliver, the wavelength Jj of a sliver mass fluctuation can be determined from the frequency f of a periodic measurement signal according to the following relationship: Q = v / f.

It is advantageous if the transmitter has at least one low pass, one high pass, one blocking pass and / or one band pass for filtering the measurement signals. The transmitter can be designed in an analog, digital or a mixed version.

It is preferred that the transmitter has means for calibrating at least one sensor, for evaluating, for phase correction, for measuring error correction, for combining and / or for forwarding the filtered measurement signals of the at least two sensors.

[034] For phase correction of the filtered measurement signals from various sensors, the transmitter can have a phase shifter, in particular an all-pass. This is particularly useful if the filtered measurement signals are combined further.

[035] It is particularly advantageous if the transmitter has a computer, in particular a microprocessor. This is preferably designed for calibration of at least one sensor, for evaluation, for phase correction, for measurement error correction, for combining and or for forwarding the measurement signals.

In a particularly preferred embodiment, the transmitter filters out the measurement signals of a first sensor for detecting the long-wave band mass fluctuations and the measurement signals of a second sensor for detecting the short-wave or the short- and long-wave band mass fluctuations.

[037] It is particularly advantageous if the first sensor is a narrowband sensor and the second sensor is a broadband. A mechanical sensor can in particular be present as the first, narrow-band sensor. The second sensor can in particular be a mechanical sensor with a smaller moving mass than the first sensor, a pneumatic, a capacitive, an optical, an acoustic, a radioactive sensor or a microwave sensor.

[038] A spinning preparation machine according to the invention has at least one measuring device of the type described here in order to achieve the advantages according to the invention.

At least one measurement preview can be used to measure the tape mass and / or the Belt mass fluctuations of the incoming fiber structure can be arranged at the entrance of the spinning preparation machine or at the input of a processing stage of the spinning preparation machine. At least one measuring device for measuring the sliver mass and / or the sliver mass fluctuations of the emerging fiber structure can also be arranged at the exit of the spinning preparation machine or at the exit of a processing stage of the spinning advance machine. However, it is preferred if at least one measuring device is arranged at the input of the spinning preparation machine or at the input of a processing stage of the spinning preparation machine and at least one measuring device is arranged at the output of the spinning preparation machine or at the output of a processing stage of the spinning preparation machine. [041] It is also advantageous if the spinning preparation machine prepares for feedback or feed-back signals from a measuring device (3 or 1) for the purpose of processing, in particular for controlling the gain, signals of at least one sensor in the spinning mill - Upstream or downstream measuring device (1 or 3) is formed in at least one frequency range. [042] Further advantages of the invention are described in the following exemplary embodiments. 1 shows an overall illustration of a spinning preparation machine according to the invention, [044] FIG. 2 shows an exemplary embodiment of a measuring device according to the invention,

[045] FIG. 3-5 further exemplary embodiments of a measuring device according to the invention,

[046] Figure 6, 7 two examples of a sensor arrangement with double mechanical scanning. [047] FIG. 8 shows an example for different frequency responses of two sensors

[048] FIG. 1 shows a draw frame as an exemplary embodiment according to the invention of a spinning preparation machine. A fiber structure FV, which consists of a single band or a combination of several bands, runs through the route in the direction of the arrow LR. First of all, the incoming fiber structure FV runs through the measuring device 1 for detecting the strip mass and / or the strip mass fluctuations. The fiber structure FV is presented to the drafting unit 2, which consists of the input roller pair 21, the middle roller pair 22 and the delivery roller pair 23. Due to the different peripheral speeds of the pairs of rollers, the sliver FV, z. B. warped by a factor of 6. The delivery roller pair 23 generally has a constant speed, so that the stretching process is regulated by influencing the speed of the other two roller pairs. The emerging fiber structure FV passes the measuring device 3 and is placed in a can 4 by means of a belt guide means 41. [049] The measuring device 1 for the incoming fiber structure FV a has a first sensor 11, which is designed here as a touch-groove roller system. Such a sensor has an essentially time-invariant transmission function and is largely insensitive to external interference. Due to the inertia of the movable probe element, however, such a sensor is not able to reproduce high-frequency changes in the measured variable. As a result, a touch-groove roller system can be considered as a sensor with high accuracy but limited bandwidth.

[050] Furthermore, the measuring device 1 has a second sensor 12. The sensor 12 can in particular be designed as a pneumatic, capacitive, optical, acoustic, radioactive sensor or as a microwave sensor. Alternatively, a mechanical sensor with a low moving mass, for example a sensor with a leaf spring, is also possible. It is only preferred that the transmission function of the second sensor 12, for the purpose of detecting the high-frequency fluctuations in the band mass, is broadband than the transmission function of the first sensor 11.

The measurement signals from sensors 11, 12 are fed to transducer 10 via transducers 110, 120. The measuring transducers 110, 120 essentially have the task of converting the measuring signals into an electrical variable.

[052] The transmitter 10 primarily generates control data SD1 from the measurement signals from the sensors 11, 12, which are fed to the regulating unit 5. The regulating unit 5 is designed to influence the peripheral speed of the input roller pair 21 and the middle roller pair 22. The measuring device 1, the regulating unit 5 and the drafting device 2 thus form an open control loop, also called a controller, for regulating the drawing of the running fiber structure FV. If, for example, the measuring device 1 detects a thick spot in the running fiber structure, that is to say a fluctuation in the tape mass, corresponding control data SD1 are transmitted to the regulator unit 5. As soon as the thick point has reached the drafting system, the input roller pair 21 and the middle roller pair 22 are braked and the speed difference with respect to the delivery roller pair 23 is increased. As a result, the sliver is stretched relatively more and the thick point is dissolved.

[053] In addition, the measuring transformer 10 can be designed to obtain quality data of the incoming fiber bundle FV. This can be useful, for example, if the upstream spinning preparation machine, for example a comber, does not have a means of checking the quality of the fiber bundle that is running out. In this case, the quality data QD2 are transmitted to an evaluation unit 6 described in more detail below. The fiber assembly FV emerging from the drafting device 2 passes through it Measuring device 3. The measuring device 3 is constructed similarly to the measuring device 1. It has a narrow-band sensor 31 and a broad-band sensor 32. The signals from the two sensors are fed to the measuring transducer 30 via measuring transducers 310, 320. The measuring transducer 30 primarily generates quality data QD1 from the measurement signals, which relate to the fiber bundle FV that is coming out and is evaluated by the evaluation unit 6. The evaluation unit 6 is designed for the calculation, display and / or storage of quality data of the fiber bundle FV that is running out.

[055] In addition, it is possible for the transmitter 30 to generate data SD2 from the measurement signals of the sensors 31, 32 for regulating the stretching process. These data SD2 are then fed to the regulating unit 5 and can then be used as a basis for regulating the peripheral speed of the roller pairs 21, 22. The measuring device 3, the regulating unit 5 and the drafting device 2 thus form a closed control loop for regulating the drawing process. The closed control loop is not suitable for correcting short-wave disturbances in the belt mass, since the disturbance is only detected when it has already left the regulating drafting system. However, the measuring device 3 detects z. For example, if the average of the strip mass increases, control data SD2 are generated and sent to the regulating unit 5, which then reduces the speed of the roller pairs 21, 22. As a result, the fiber structure FV is stretched to a greater extent and the average tape mass of the fiber structure FV that is running out is reduced. The controller unit 5 is expediently designed such that the data SD1 of the open control loop and the data SD2 of the closed control loop can be processed simultaneously. [056] FIG. 2 shows a measuring device 1 according to the invention with a downstream regulating unit 5 and evaluation unit 6. The measuring device has a narrow-band sensor 11, a broad-band sensor 12 each with an associated transmitter 110, 120. The measurement signals of the first sensor 11 are filtered by a low-pass filter 17, so that a signal x tp2 is generated and fed to the microprocessor 14. Furthermore, the signals of the broadband sensor 12 are filtered via a low pass 16, a signal x being generated and fed to the microprocessor 14. The tpi low-pass filters 16, 17 have a similar pass characteristic. The pass characteristic is determined such that the pass range lies in the working range of both sensors 11, 12. In this way signals x and x are obtained which can be sensibly compared in terms of amplitude tpl tp2. By comparison, the microprocessor 14 can now determine a deviation in the gain factor, also called the proportionality factor. An actuating signal z for regulating the amplifier 13 can now be determined from this. The subsystem from the broadband sensor 12, the transducer 120 and the amplifier 13 can be assigned a constant gain. The output signal x of the amplifier 13 is thus independent of a systematic amplitude error of the sensor 12. In particular, measurement errors which are caused by band parameters are corrected. If, for example, the broadband sensor 12 is based on an optical measurement principle, the measurement error which is generated by a change in the color of the fiber structure FV is corrected. A long-term drift of the sensor 12, which is compensated for by external influences, such as a change in the air humidity, can also be compensated for. The output signal x of the amplifier 13 thus contains precise and broadband information about the band mass or the fluctuation of the band mass of the fiber structure FV and can easily be converted into a control signal SD1 by the microprocessor 14 and passed on to the regulating unit 5.

The output signal x of an ^hp high-pass 15 and the output signal x tp2 of the low-pass 17 are used to determine quality data QD2. The signals from the second sensor 12 are filtered by the high pass 15. The high pass 15 and the low pass 17 preferably have the same cutoff frequency, so that the data stream QD2 contains a broadband image of the fluctuations in the band mass of the fiber structure FV. Alternatively, the output signal of the amplifier x could also be used to generate the quality data QD2. Using the quality data QD2, the evaluation unit 6 can now determine common parameters of the fiber structure, such as the strip weight deviation A%, the variation coefficient CV or a variation coefficient CV length. Several CV length coefficients can also be determined, which refer to different lengths of the fiber structure. Spectral analysis can also be carried out. [058] FIG. 3 shows a further embodiment of a measuring device 1 according to the invention. The arrangement of the sensors 11, 12 and the measuring transducers 110 and 120 corresponds to the previously described embodiment. The signals from the narrow-band sensor 11 are fed to a summer 25 via a low-pass filter 17 and a phase shifter, which is designed here as an all-pass filter 19. Furthermore, the measurement signals of the broadband sensor 12 are fed to the same summer 25 via a high pass 15 and an amplifier 13. The output signal xs of the adder 25 is an accurate and broadband image of the band mass fluctuations of the fiber structure FV, provided the cutoff frequency of the high pass 15 and the cutoff frequency of the low pass 17 correspond to one another. In other words, the signals above the cutoff frequency are transmitted through the high pass 15 and the signals below the cutoff frequency through the low pass 17. In order to ensure that the adder 25 high and low frequency signals of corresponding amplitudes are supplied, the signal of the sensor 11 is fed to a bandpass filter 18 and its output signal x bp to the microprocessor 14. The pass band of the band pass 18 is advantageously above the cut-off frequency of the high pass 15. The microprocessor 14 now evaluates the output signal x of the band pass and the output signal x of the amplifier 13 and thus calculates an actuating signal z for regulating the gain factor of the amplifier 13. Alternatively, the low-pass filtered signals from the narrowband sensor 11 are routed via a regulated amplifier 13. [059] In order to further ensure that measurement signals from the two sensors 11 and 12, which relate to the same point on the running fiber sliver, are fed to the summer 25, the measurement signal of the sensor measuring first, here of the narrowband sensor 11, is transmitted here as a Allpass 19 implemented phase shifters. The Allpass 19 essentially has the task of forwarding the signals with a time delay but the same amplitude and is designed to be controllable with respect to the phase shift. The low-pass filter 17 connected upstream of the phase shifter also causes a delayed phase shift, but this cannot be regulated. The frequency-dependent phase delay of the all-pass is controlled by a signal z from the microprocessor 14. The signal z is generated, for example, from a comparative analysis or correlation of the signals x tp and x V. Alternatively or additionally, a buffer, not shown, which works for example according to the F st-lα / Fkst-Out principle, could also be used for the controlled phase structure. [060] The control data SD1, which are fed to the regulating unit 5, can essentially be calculated from the output signal xs of the summer 25.

The quality data QD2, which are fed to the evaluation unit 6, can be generated from the output signal x tp of the low-pass filter 17 and from the output signal x V of the amplifier 13. The band weight deviation A% can be determined in a simple manner from the signal x tp and the variation coefficient CV or the variation coefficient CV of interest can be determined from the signal x. It is particularly advantageous in this embodiment that the signal x provides a signal which contains broadband and precise information about the band mass and / or the band mass fluctuations of the fiber structure FV. The signal xs can also be used to carry out a spectral analysis. Such a measuring device 1 can preferably be used at the input of a spinning preparation machine, but in principle alternatively or additionally also at the output of the same. It is characteristic of the exemplary embodiment described that both the advantages of a narrow-band sensor 11 and the advantages a broadband sensor 12 can be optimally combined.

The measuring device 1 shown in FIG. 4 also has a broadband sensor 12 and a narrowband sensor 11. With regard to the running direction LR of the fiber structure FV, however, the sensors are spatially interchanged, i. that is, a certain point of the fiber structure FV first passes through the broadband sensor 12, then the narrowband sensor 11. This sensor arrangement is preferred if the fiber structure FV leaving the measuring device 1 is guided precisely. The structure, mode of operation and purpose of the transmitter 10 essentially correspond to the exemplary embodiment described above. However, due to the changed sensor arrangement, the allpass 19 is arranged here between the amplifier 13 and the summer 25. This means that the signals of the broadband sensor 12 are delayed before the summation with the signals of the narrowband sensor 11. As an alternative or in addition, a buffer, not shown, which works for example according to the first-in / first-out principle, could also be used for the controlled phase correction. The buffer can be used, for example, for phase correction, which is required due to the spatial separation of the sensors 11, 12, and the all-pass for correcting the phase shift, which is brought about by the filters or other elements of the arrangement. The control data SD1 and the quality data QD2 can be calculated and forwarded in the same way as in the exemplary embodiment according to FIG. 3. The measuring device 1 shown can preferably be used at the entrance to a spinning preparation machine. However, it is generally possible to arrange them alternatively or additionally at the exit of such a machine.

[063] FIG. 5 shows a simplified measuring device 3 according to the invention, which transfers quality data QD1 to an evaluation unit 6. Such a measuring device 3 is advantageously arranged at the output of a spinning preparation machine that works without a closed control loop. The measuring device 3 has a narrowband sensor 31 and a broadband sensor 32 as well as corresponding measuring transducers 310 and 320. In FIG. 5, the fiber structure FV first passes through the narrowband sensor 31, then the broadband sensor 32. Alternatively, however, the arrangement of the sensors 31, 32 can be interchanged with respect to the running direction. This is particularly useful if the broadband sensor for compressing and strengthening the fiber structure FV is configured in a shape. [064] The signals from the two sensors 31, 32 are fed to the transmitter 30. The signals from the narrowband sensor 31 are fed to the microprocessor 34 via a low pass 37. The signals of the broadband sensor 32 are over a high pass 35 and an amplifier 33 are also supplied to the microprocessor 34. The amplifier 33 is regulated via an actuating signal z, which is generated by the microprocessor 34 V on the basis of the bandpass-filtered signals from the narrowband sensor 31. This ensures that the signals y supplied to the microprocessor 34 have a comparable ampute. From this, the micro V tp processor 34 can determine the quality data QD1. These can then be fed to the evaluation unit 6.

FIG. 6 shows a sensor arrangement with double mechanical scanning. The running fiber structure FV first passes through a narrow-band sensor 11, which is designed here as a touch-groove roller unit. The fiber structure FV then passes through a broadband sensor 12, which is also designed as a mechanical sensor with a movable sensing element 124. The scanning element 124 is designed as a sliding plate and is pressed against the running sliver by a spring. The moving mass can be much smaller than with a touch-and-groove roller unit. This results in a higher bandwidth of the sensor 12. A vertical movement of the sensing element 124 is a measure of a fluctuation in the tape mass of the fiber structure FV and can be absorbed by any usual displacement sensor 125. If the sensor arrangement shown is part of a measuring device or machine according to the invention, there are also advantages already described.

FIG. 7 shows a preferred embodiment of a double mechanical scanning sensor arrangement. Sensor 12 is designed as a mechanical sensor with sensing element 224. The contact pressure of the running fiber structure FV is a measure of the strip mass or the strip mass fluctuation. The contact pressure causes an elastic deformation of the feeler element 224. This elastic deformation can be measured, for example, by a piezoelectric sensor 225. The sensor 12 is very broadband. Such a mechanical double scanning can advantageously be used in a measuring device or machine according to the invention.

With the double mechanical scanning, the sensors 11, 12 can also be arranged in a different order with respect to the running direction of the fiber structure FV. This can result in advantages with regard to the mechanical guidance of the fiber structure FV.

[068] FIG. 8 shows an example for different frequency responses of two sensors. The frequency response is the part of the transfer function related to the ampute. The frequency responses shown relate to sensor combinations 11 and 12 or 31 and 32 of the exemplary embodiments described above. The frequency f is plotted on the abscissa on a logarithmic scale from 3 to 100 Hertz. The ordinate gives - also on a logarithmic scale - depending on the frequency f the relative amplitude of the respective sensor signal based on a standard value K again. Curve A (f) shows the frequency response of a narrowband sensor (see sensors 11, 31 in FIGS. 1-7) and curve A 12 (f) shows the frequency response of a broadband sensor (see sensors 12, 32 in FIGS. 1-7) ). The dimension of the factor K corresponds to the dimension of the output signals of the transducers 110 or 310 and 120 or 320. The numerical value of K describes a setpoint.

[069] A mechanical sensor 11 or 31 with a movable sensing element approximately has a P-T transmission behavior. The curve A (f) shows such a frequency response as an example. For frequencies lower than approximately 10 Hz, the sensor 11 or 31 has an almost constant gain. With increasing frequency, the amputee initially shows an increase in resonance and then a steady drop of about 40 dB per decade. In addition, it should be pointed out that the resonance increase depends on a damping constant of the respective sensor and decreases or even disappears with stronger damping.

[070] Broadband sensors 12 and 32 often have a P-T transmission behavior. The curve A (f), which is an example of this, has an almost constant amplification at frequencies below approximately 30 Hz. However, the amputee is 10 dB above the setpoint. This deviation in the ampute depends on disturbance variables and changes with them over time. For higher frequencies, the ampute decay is 20 dB per decade.

[071] If sensors with such frequency responses are used in combination, the frequency range of 0 to 30 Hz that is of interest, for example, can be divided into intervals 1 and 2. The narrowband sensor 11 or 31 has an essentially constant gain in the interval 1, while the broadband sensor 12 or 32 shows this property in both intervals.

[072] From the signals of the narrowband sensor 11 or 31 and the broadband sensor 12 or 32, signal sections in the area of the interval 1 can be obtained by filtering, for example with a bandpass. These signal sections are free from disturbing resonance and ampute decay effects. Thus, the amplitude difference of the signal sections for gain control for the broadband sensor 12; 32 can be used. In the example, curve A (f) is corrected by -10 dB.

[073] A signal which represents the entire measuring range from 0 to 30 Hz can be obtained, for example, by using interval 1 from the signals of the narrowband sensor 11 or 31 and the interval from the amplitude-corrected signals from the broadband sensor 12 or 32 2 is filtered out and these two filtered signals are combined.

[074] Since the transfer functions shown only relate to the alternating component of the signals, it may also be necessary to adjust the equal components of the signals (offset). The present invention is not limited to the exemplary embodiments shown and described. Modifications within the scope of the claims are possible at any time.

Claims

Expectations

[001] Method for measuring the strip mass and / or the strip mass fluctuations of a running fiber structure, in particular on a spinning preparation machine, wherein signals of several sensors which register the strip mass or strip mass fluctuations are processed with at least partially different transfer functions, characterized in that from the at least one defined frequency range is filtered out in a measurement signal of at least one sensor and at least part of the filtered signal is used in the processing of signals of at least one further sensor.

[002] Method according to claim 1, characterized in that at least one frequency range is selected so that the respective sensor in this area has a transmission function with constant amplification and preferably constant phase response.

Method according to claim 1 or 2, characterized in that the frequency range of the band mass fluctuations to be detected is divided into several, essentially non-overlapping intervals, and this frequency is filtered out from the signals of different sensors.

Method according to claim 3, characterized in that a specific sensor is assigned to each interval, which sensor has a transmission function with constant ampute rate in the respective interval.

[005] Method according to one or more of the preceding claims, characterized in that at least one high pass, low pass, band pass or a band stop is used for filtering the measurement signals.

[006] Method according to one or more of the preceding claims, characterized in that the signals are filtered such that they can be used directly for controlling a process and / or for recording quality data of the fiber structure.

[007] Method according to one or more of the preceding claims, characterized in that the filtered signals from at least one sensor are used to obtain data for the correction of at least one further sensor and / or for correcting the measurement errors of at least one further sensor.

[008] Method according to one or more of the preceding claims, characterized thereby. that measurement results that were measured in a common frequency range by the at least two sensors are compared and used for calibration and / or for measuring error correction of the measurements of at least one sensor. Method according to one or more of the preceding claims, characterized in that measurement signals of a sensor working according to a mechanical principle are preferably used with a scanning and grooving roller unit for the calibration and / or the correction of the measurement errors of a further sensor operating according to a different measurement principle become.

[010] Method according to claim 8, characterized in that measurement signals of the sensor working according to a mechanical principle are further processed with preferably a sensing and grooving roller unit instead of unusually deviating measurement signals of the further sensor working according to another measurement principle.

[011] Method according to claim 8 or 9, characterized in that a sensor which works according to a further mechanical principle, a pneumatic, a capacitive, an optical, an acoustic, a radioactive sensor or a microwave sensor is used as a further sensor.

[012] Method according to one or more of the preceding claims, characterized in that the filtered signals of at least two sensors are combined for the purpose of controlling a process and / or for recording quality data of the fiber structure.

[013] Method according to one or more of the preceding claims, characterized in that a phase difference in the signals of at least two sensors is compensated.

Method according to one or more of the preceding claims, characterized in that from the measurement signals of a first sensor, a low-frequency area for detecting the long-term fluctuations in the tape mass, and from the measurement signals of a second sensor, a high-frequency or broadband area for detecting the short-wave or the short - and long-term fluctuations in strip mass are filtered out.

[015] Method according to claim 13, characterized in that the first sensor is a narrowband, in particular a mechanical sensor and / or the second sensor is a broadband, in particular a mechanical sensor with a smaller moving mass than the first sensor, a pneumatic, a capacitive, an optical, an acoustic, a radioactive sensor or a microwave sensor is used.

Device for measuring the tape mass and / or the tape mass fluctuations of a running fiber structure, in particular according to the method according to one or more of the preceding claims, with - a measuring transducer (10; 30) and - a plurality of sensors (11, 12; 31 , 32) with at least some differences Transfer functions, characterized in that the transmitter (10; 30) is designed such that it filters out a defined frequency range from the measurement signal of at least one sensor (11, 12; 31, 32) and uses it when processing the signals of at least one further sensor.

Apparatus according to claim 15, characterized in that the transmitter (10; 30) is designed such that it divides the frequency range to be detected into several intervals in order to determine the band mass fluctuations and filters out these frequency intervals from the signals of different sensors.

[018] Device according to claim 15 or 16, characterized in that the transmitter (10; 30) has at least one low pass (16, 17), a high pass (15), a blocking pass and / or a band pass (18) for filtering the measurement signals ,

[019] Device according to one or more of claims 15 to 17, characterized in that the transmitter (10; 30) has means for equipping at least one sensor, for evaluation, for time correction, for measurement error correction, for combining and / or for forwarding the filtered measurement signals of the at least two sensors (11, 12; 31, 32).

[020] Device according to one or more of claims 15 to 18, characterized in that the transmitter (10; 30) has at least one phase shifter, in particular an all-pass (19), for phase correction of the filtered measurement signals of at least two sensors.

Device according to one or more of claims 15 to 19, characterized in that the transmitter (10; 30) has a computer, in particular a microprocessor (14; 34), for cleaning at least one sensor and or for evaluation and / or Has time correction and / or measurement fire correction and / or combination and / or forwarding of the measurement signals.

[022] Device according to one or more of claims 15 to 20, characterized. that the transmitter (10; 30) filters out the measurement signals of a first sensor (11; 31) for detecting the long-tailed band mass fluctuations as well as the measurement signals of a second sensor (12; 32) for detecting the short-walled or short and long-length band mass fluctuations.

[023] Device according to claim 21, characterized in that the first sensor (11; 31) is a narrow-band, in particular a mechanical sensor (11; 31) and the second sensor (12; 32) is a broad-band, in particular a mechanical sensor (11 ; 31) with less moving mass than the first sensor (11; 31), a pneumatic, a capacitive, an optical, an acoustic, a radioactive Sensor or a microwave sensor. Spire preparation machinery, in particular a carding machine, draw frame, cooling machine or a multi-stage machine, with - at least one open or closed control loop, the at least one measuring device (1; 3), a control unit (5) and at least one drafting device (2) for stretching comprises a running fiber structure (FV) and is designed to regulate band mass fluctuations of the fiber structure (FV) and / or - a belt monitoring unit which comprises at least one measuring device (1; 3) and an evaluation unit (6) and for calculation, display and / or storage of quality data of the running fiber structure (FV), characterized in that the spiral preparation machine comprises at least one measuring device (1; 3) according to one of Claims 15 to 22.

Spinning preparation machine according to claim 23, characterized in that at least one measuring device (1) at the input of the spinning preparation machine or at the input of a processing stage of the spinning preparation machine and / or at least one measuring device (3) at the output of the spinning preparation machine or at the output of the processing stage of Spinning preparation machine is arranged.

Spinning preparation machine according to claim 23 or 24, characterized in that it at least for guiding the feedback or feeding forward signals of a measuring device (3 or 1) for the purpose of use in processing, in particular in the regulation of the gain, of signals a sensor of a measuring device (1 or 3) upstream or downstream in the spinning mill is formed in at least one frequency range.