Classifications

• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01H—SPINNING OR TWISTING
  • D01H13/00—Other common constructional features, details or accessories
  • D01H13/14—Warning or safety devices, e.g. automatic fault detectors, stop motions ; Monitoring the entanglement of slivers in drafting arrangements
  • D01H13/16—Warning or safety devices, e.g. automatic fault detectors, stop motions ; Monitoring the entanglement of slivers in drafting arrangements responsive to reduction in material tension, failure of supply, or breakage, of material
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01H—SPINNING OR TWISTING
  • D01H1/00—Spinning or twisting machines in which the product is wound-up continuously
  • D01H1/08—Spinning or twisting machines in which the product is wound-up continuously cup, pot or disc type, in which annular masses of yarn are formed by centrifugal action

Definitions

• the invention relates to a method for centrifuging with the features mentioned in the preamble of claim 1 and a device for centrifuging with the features mentioned in the preamble of claim 7.
• a fiber sliver stretched in a drafting system for example placed in a spinning can, or a roving in the form of a flyer bobbin, which is also referred to as a sliver, is introduced into a rotating spinning centrifuge by means of a changeable and lowerable thread guide, spun into a thread and so-called Spin cake placed on the inside wall of the spinning centrifuge.
• This means that the fuse emerging from the mouth of the thread guide is conveyed to the inner wall of the spinning centrifuge under the influence of an air flow circulating with the spinning centrifuge, and is fixed there so that a twine leg rotating about the centrifuge axis is produced.
• this thread leg gives the thread to be produced the necessary rotation before it is placed on the rotating inner surface of the centrifuge as a spin cake.
• the thread material spun up to this point in time is rewound onto a rewinding tube introduced into the centrifuge.
• This winding process is initiated, for example, by advancing the winding tube into the path of the yarn leg.
• the winding tube detects with her Edge of the sleeve emerging from the thread guide, rotating yarn leg, whereby the spin cake deposited on the inner wall of the spinning centrifuge is wound onto the winding tube.
• This winding process can lead to yarn breakage, which means that when the yarn package is wrapped around the winding tube, a package residue remains in the centrifuge.
• twine residues also restrict, among other things, the already relatively limited receiving volume of the spinning centrifuges, it is important in the interest of the highest possible effectiveness of a centrifuge spinning machine to quickly identify a twine residue remaining in a centrifuge and to initiate appropriate countermeasures.
• a process for pot spinning is known from DE 195 23 835 A1, in which the period of rotation of the yarn legs rotating in the spinning centrifuges is measured.
• the material supply is usually interrupted.
• This means that the roving delivery is interrupted by a so-called sliver stop device.
• sliver stop devices arranged in the area of the drafting systems are known, for example, from DE 38 22 930 A1.
• the invention has for its object to provide a method and a device by means of which it can be ensured in a simple and cost-effective manner that the individual spinning centrifuges of a centrifugal spinning machine at the beginning of the spinning cycle are optimal , especially empty condition.
• the rotational frequency of the rotating leg of yarn is measured by means of a thread sensor which detects the movement of the thread.
• a thread sensor arranged between the drafting system and the oscillating, tubular thread guide detects a rotational thread movement which occurs in the region of the thread sensor and corresponds to the rotational frequency of the thread leg in the spinning centrifuge.
• This rotational thread movement which is also referred to as the thread balloon and corresponds to the rotational frequency of the yarn leg, is filtered out from the noise signal determined by means of the thread sensor and representing the movement of the thread.
• the noise signal is conducted, for example, via a filter stage, which determines a frequency signal based on the rotational frequency of the yarn leg.
• the processing of this frequency signal for example by means of Fast Fourier transformation or the like, leads to frequency lines lying in certain spectral ranges, which can be clearly assigned to certain free radii within the centrifuge.
• the respective rotational frequency of the yarn legs is detected simultaneously at all workplaces. Since in a measuring and evaluation unit there is a clear assignment to each spinning station, a comparison of the rotational frequencies of the yarn legs with one another can immediately determine whether and in which of the spinning centrifuges there is still a package residue. Since it can be assumed that a package residue occurs relatively rarely and even more rarely at several workplaces at the same time, the determined rotational frequencies of the yarn legs can also be compared with one another so that an external setpoint value can be dispensed with. The spinning stations, which have no package residue, quasi deliver an internal setpoint. If a package residue is found in a spinning centrifuge, the evaluation unit immediately sends a corresponding control signal to the sliver stop device of the job in question. This means that the further feeding of roving is stopped at the relevant job.
• the centrifuge spinning machine has a sensor device which makes it possible to detect at least one of the physical values occurring during a spinning cycle.
• the detected value is e.g. in a workstation computer or a central spinning machine computer, compared with a target value and the result of this comparison is used to determine the loading state of the individual spinning centrifuges.
• the sensor device is preferably designed as a thread sensor arranged between the drafting device and the thread guide and detecting the presence of a thread. Because this thread sensor is assigned a filter stage, a signal corresponding to the rotational frequency of the yarn leg can be filtered out of the thread sensor output signal and is used in an evaluation circuit for comparison with a target signal. In this way, the rotational frequency of the yarn legs rotating with the spinning centrifuges can be determined and evaluated without large structural measures, which may require additional installation space. That means that only a filter stage and a comparator comparing the signals are additionally necessary in order to modify an existing device such that the presence of a package residue in one of the spinning centrifuges can be deduced immediately by measuring the rotational frequency of the package legs.
• the centrifuge spinning machine has a central control device in which the signals supplied by the individual thread sensors are evaluated with regard to the determined rotational frequencies of the yarn legs. This advantageously makes it possible to carry out a comparison with the setpoint in a compact device, the setpoint only having to be made available once for all spinning positions.
• FIG. 1 schematically shows a centrifuge spinning machine 10 which has a large number of work stations 12.
• FIG. 1 shows a section of three of these work stations 12, 12 'and 12 ".
• Each work station 12 in each case comprises a spinning centrifuge 14, which is supported in (not shown) magnetic bearings and rotates at high speed.
• the spinning centrifuges 14 are each assigned a changeable tubular thread guide 16 which can be lowered in the R direction, the longitudinal axis of which lies in the axis of rotation of the spinning centrifuge 14.
• a roving 24 is fed into the spinning centrifuge 14 by the thread guide 16 and is deposited as a spinning cake 8 on an inner wall 22 of the rotating centrifuge 14, forming a yarn leg 20.
• the rotation of the centrifuge 14 creates a finished spun thread 18 from the roving 24.
• the roving 24 is drawn before it is fed into the spinning centrifuge in a drafting device 26, which is only indicated in FIG.
• the thread guides 16 are each assigned a drive device, not shown, which both gives the thread guides 16 a constant axial charging movement CH and also continuously lowers the thread guides 16 in direction R during the spinning process.
• Each spinning station 12 is also assigned a thread sensor 28, preferably in the area of the thread guide input the presence of the roving 24 or the resulting thread 18 is detected.
• the thread sensor 28 can be combined in a manner not described here with an injector (not shown) which ensures that the roving 24 is threaded into the thread guide 16 and the spinning unit 12 can be spun on. That is, such an injector sucks in the roving 24 emerging from the drafting device 26 and blows it into the thread guide 16.
• centrifuge spinning machine 10 In the context of the present description, further details of the centrifuge spinning machine 10 are not to be discussed, since these are generally known.
• the centrifuge spinning machine 10 shown in FIG. 1 has the following function:
• the roving emerging from the mouths of the respective thread guide 16 lies against the inner wall 22 of the rotating spinning centrifuge 14, forming a yarn leg 20, so that a yarn leg 20 is formed which rotates with the spinning centrifuge 14.
• the resulting thread 18 is deposited on the inner wall 22 of the spinning centrifuge 14 as a package (spin cake 8), as indicated by the broken line in FIG. 1 using the example of the work station 12 ′′.
• the centrifuges 14 (not shown) are wound around the reels onto which the packages 8 are wound.
• a spinning centrifuge 14 is shown schematically in a top view.
• the axis of rotation 32 of the spinning centrifuge 14 coincides with the longitudinal axis of the tubular thread guide 16.
• the roving 24 or thread 18 emerging from the thread guide 16 bears against the rotating inner wall 22 of the spinning centrifuge 14 to form a thread leg 20 and is carried along in the direction ⁇ .
• the thread 18 is deposited on the inner wall 22 at a constant delivery speed (winding speed) V L.
• the centrifuge 14 rotates at a constant angular velocity ⁇ .
• the rotational frequency of the yarn leg 20 is designated by f G and the rotational frequency of the inner wall 22 of the centrifuge by f Z.
• the twine legs 20 generally rotate at a rotational frequency f G , which corresponds to the inside radius r of the spinning centrifuge 14, around the thread guide 16.
• the movement of the respective roving 24 or the threads 18 is detected by means of the thread sensors 28.
• This movement leads to a thread sensor output signal, which indicates as a noise signal that the respective thread 18 is moving and is therefore present.
• the delivery speed V L of the thread 18 is superimposed by the twisting in accordance with the rotational frequency f G of the yarn leg 20 by a further thread movement.
• This additional thread movement is directly proportional to the rotational frequency f G of the yarn leg 20.
• the thread sensor output signal detected by the thread sensors 28 consequently contains, in addition to the movement information corresponding to the delivery speed V L of the thread 18, a signal component corresponding to the rotational frequency f G of the yarn leg 20.
• the thread sensors 28 are connected to a control device 40 via signal lines 38.
• the control device 40 has, as the schematically enlarged illustration in FIG. 1a shows, one of the number of work stations 12 of the centrifuge spinning machine 10 corresponding number of inputs 42, so that each thread sensor output signal of each winding unit 12 can be processed individually.
• the inputs 42 are each connected to a filter module 44, each of which is followed by a frequency evaluation module 46.
• the frequency evaluation modules 46 are in turn connected to a comparator 48, which is also connected to a memory element 50.
• the comparator 48 is connected to the outputs 52 of the control device 40, again a corresponding number of outputs 52 being provided in accordance with the number of work stations 12 of the centrifuge spinning machine 10.
• Each of the outputs 52 is connected to a so-called match stop device 54, which is assigned to the work stations 12 and is not shown, which, when activated appropriately, ensures that the material delivery is prevented by the respective drafting device 26.
• control device 40 which usually takes over the control functions for monitoring the operation of the centrifuge spinning machine 10
• the output signals of the thread sensors 28 can be evaluated in the sense of the invention, for example, as follows, it being expressly pointed out here that the control device 40 controls the Of course, thread sensor output signals can also be evaluated in another way.
• the output signals of the thread sensors 28 are passed through the filter modules 44. These are designed, for example, as bandpass filters. As a result, signal components in a specific frequency band are filtered out of the applied noise signal, which are in the range of Balloon frequency lie on the thread sensor 28. This filtered-out frequency range is then passed over the frequency evaluation modules 46.
• a spectral analysis can be carried out by means of a Fast Fourier transform or other known frequency evaluation methods in such a way that the spectral components corresponding to the additional thread movement and thus the rotational frequency f G of the yarn leg 20 are filtered out. These are then compared in the comparator 48 with stored target values, which are provided, for example, by the storage element 50.
• the rotational frequency f G of the yarn legs 20 can be calculated in advance. If this reveals that the rotational frequency f G of the twine leg 20 is lower than the desired value, this is due to a smaller free diameter r and thus to the presence of a twine residue 30 in the relevant spinning centrifuge 14.
• a signal assigned to the corresponding work station 12 is then delivered via the comparator 48 to the corresponding output 52, so that the material supply to the work station 12 ′ in question is immediately interrupted via a known sliver stop device 54 which is therefore not shown and explained in detail.
• the rotational frequencies f G of the yarn legs 20 of the work stations 12 can be compared with one another by means of the comparator 48.
• the rotation frequency of the yarn leg does not have to be determined via the thread sensor 28 explained in the above exemplary embodiment.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Textile Engineering (AREA)
• Spinning Or Twisting Of Yarns (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=7918309

Family Applications (1)

Country Status (7)

Families Citing this family (7)

Family Cites Families (13)

• 1999
  • 1999-08-13 DE DE19938433A patent/DE19938433A1/de not_active Withdrawn
• 2000
  • 2000-07-07 DE DE50005862T patent/DE50005862D1/de not_active Expired - Fee Related
  • 2000-07-07 EP EP00114596A patent/EP1076123B1/de not_active Expired - Lifetime
  • 2000-08-09 CZ CZ20002932A patent/CZ300010B6/cs not_active IP Right Cessation
  • 2000-08-10 US US09/636,323 patent/US6389788B1/en not_active Expired - Fee Related
  • 2000-08-11 CN CNB001226371A patent/CN1225576C/zh not_active Expired - Fee Related
  • 2000-08-11 RU RU2000120955/12A patent/RU2000120955A/ru not_active Application Discontinuation
  • 2000-08-14 JP JP2000246080A patent/JP2001081634A/ja active Pending

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