CH663427A5 - METHOD AND DEVICE FOR DETERMINING THE MEDIUM FINENESS AND THE VARIATION COEFFICIENT OF THE FINE DETERMINATIONS OF TEXTILES AND TECHNICAL SPINES. - Google Patents

Description

The present invention avoids these disadvantages and relates to a method and a device for automatically determining the average fineness and the coefficient of variation of the fineness fluctuations of textile and technical yarns, rovings and tapes according to the features defined in claims 1 and 8.

The invention is essentially to be seen in the fact that the fineness determination and the uniformity test are carried out in a single test process and with the same test material sections.

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663 427

However, the measuring devices available for the uniformity test generally only allow the determination of the relative fluctuations in fineness, but not the determination of the absolute mean fineness. Therefore, in the combination according to the invention, the test material is collected in a weighing pan during the uniformity test, and the weight of a defined sample length and thus the absolute mean fineness are determined.

The calculation of the coefficient of variation CV (L) for test material sections of length L, however, takes place from the signal current generated by the measuring element in the uniformity tester. This gives you the following advantages:

- the time-consuming cutting and weighing of individual sections for determining the fineness is eliminated;

- The fineness is determined in the same step as the uniformity test with only insignificant additional costs;

- The elaborate additional changer including device for automatic cutting and cutting of the test material sections for the fineness determination is not necessary.

An embodiment of the invention is explained in more detail with reference to the figure.

The uniformity tester 1 comprises, among other things, a measuring element 2, a changer 3, a separating device 4, an insertion arm 5, an accurate pull-off device 7, an electronic balance 9 and a blowing or suction device 8. The presentation units 6 to be checked are accommodated in a frame 16 .

An evaluation unit 10 is connected to the uniformity tester 1. It includes, among other things, an analog-digital converter 11 and a computer 12. The measurement value is output via an output module 13, for example a printer.

The procedure for a test is as follows: The operator threads the ends of the presentation units 6 (test item 14) into the changer 3 and selects the test conditions. At the start of the test, insert arm 5

the end of the first packaging unit into the measuring element 2 and into the take-off device 7. The test is carried out over a predetermined length of material per packaging unit, e.g. 1000 meters. After having passed this length, the test 5 is separated 14 with the separating device 4 and the end of the second packaging unit is inserted and so on until all of the 10 packaging units 6, for example 10 presented, have been tested. In the present example, 10 x 1000 m of test material then lie on the weighing pan of the scale 9, which is now weighed automatically. The result of the weighing is sent to the computer 12, which uses it to determine the average fineness x.

During the test, the signal from the measuring element 2 also passes via the analog-digital converter 11 to the computer 15 12, which is e.g. the coefficient of variation CV (L) of the fluctuations in the mass of e.g. L = 100 m test specimen sections calculated.

The calculated value CV (L) and the average fineness are output in a suitable form via the output module 13 (e.g. printer).

Of course, the system according to the invention can be programmed in a known manner in such a way that all the usual types of variation coefficients or other statistical parameters, such as, for example, standard deviation, highest and lowest value, and others, can be calculated and output.

Furthermore, the characteristic values for fluctuations within and between the packaging units can be determined by recording the mass of the test item in the weighing pan after each individual test in order to calculate the fineness fluctuations between the packaging units.

If necessary, the weighing pan can also be emptied automatically after the weight has been taken over by the computer 12 at the end of each individual test by means of a blowing or suction device 8.

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Claims (12)

663 427 1.Procedure for determining the average fineness and the coefficient of variation of the fineness fluctuations of textile test material in the form of textile and technical yarns, rovings and tapes on at least one packaging unit, the test material being subjected to a uniformity test and the resulting measurement signal being fed to a computer, characterized in that, after passing through the measuring element (2), the test material (14) is placed on a scale (9) arranged downstream of the uniformity tester (1), so that the weight of test material sections of a predetermined length is determined and also fed to the evaluation unit (10) and that the absolute average fineness and, in combination with the non-uniformity, the coefficient of variation of the relative fineness fluctuations are calculated in the computer (12) from the measured values weight / test material section and edited in an output module (13). 2. The method according to claim 1, characterized in that in addition to the average fineness and the coefficient of variation, further statistical parameters, such as standard deviation, frequency distribution, extreme values, are determined. 2nd PATENT CLAIMS 3. The method according to claim 1, characterized in that the bowl of the scales (9) is only emptied after the weight has been taken over by the evaluation unit (10) after checking all presented presentation units (6). 4. The method according to claim 1, characterized in that after each individual test, the weight is read on the balance (9) and the mean value of the fineness is determined for each individual test by forming the difference between the respective weights. 5. The method according to claim 1, characterized in that after each individual test the weight is read on the scale (9) and then the weighing pan is emptied. 6. The method according to claim 2, characterized in that the statistical characteristic values for the fluctuations of the fineness within and / or between and / or within groups of presentation units (6) are determined. 7. The method according to claim 5, characterized in that the weighing pan is emptied automatically. 8. Apparatus for carrying out the method according to claim 1, with a uniformity tester and an evaluation unit, characterized by a scale (9) arranged downstream of the uniformity tester (1), in the shell of which at least one presentation unit (6) related test material sections (14) of a predetermined length after passing the measuring element (2), the evaluation unit (10) being able to determine both the mean absolute fineness of each test material section and the coefficient of variation of the relative fineness fluctuations and to make them displayable in the output module (13). 9. The device according to claim 8, characterized in that the test material (14) is stacked in presentation units (6), that one presentation unit after the other can be selected by a changer (3), from which the test product (14) by means of an insertion arm ( 5) can be inserted into the measuring element (2) and can be advanced by a pull-off device (7) for a predetermined time or during a predetermined number of revolutions and can be deposited on the scale (9) from there. 10. The device according to claim 9, characterized in that the measuring element (2) of the uniformity tester (1) is a plate capacitor. 11. The device according to claim 9, characterized in that the measuring element (2) of the uniformity tester (1) is an optical measuring element. 12. The apparatus according to claim 9, characterized by a blowing or suction device (8) for emptying the weighing pan. On textile and technical yarns, rovings and tapes, or spun yarns, two criteria are checked as part of operational quality control: - the so-called non-uniformity with the help of uniformity testers and - The mean fineness and the coefficient of variation of the fineness using a combination of a scale and a calculator. The non-uniformity is tested in a known manner in such a way that the test material is pulled through a suitable measuring element at a constant speed, for example through a capacitive measuring element. This measuring device converts the fluctuations in mass of the test material into proportional signal current fluctuations. Suitable electronic computers evaluate these fluctuations, e.g. to to calculate the coefficient of variation CV (L) of sections of the same length. The length L of the test material sections is usually short, for example 8 millimeters, in the uniformity test. In certain cases, however, one is also interested in the coefficient of variation of the mass fluctuations of longer test specimen sections, for example, L = 100 meters. Modern computers are easily able to calculate the variation coefficients of the mass fluctuations of test pieces of the same length L from the signal current fluctuations mentioned above. Since the uniformity check is only carried out on a random basis, the check must be extended to several so-called presentation units in order to ensure sufficient statistical certainty. Presentation units are e.g. Yarn bobbins, roving bobbins, cans on belts, etc. In the sense of rationalization, modern uniformity testers are provided with changers which enable the automatic transition from one packaging unit to the next. The average fineness and the fineness fluctuations are determined in such a way that test product sections of the same length are initially produced by measuring the length and cutting of several packaging units. Each of these sections is weighed and the resulting length-related mass is evaluated by hand or in computers. Here, too, the desired statistical reliability of the measurement results requires the tests to be extended to several presentation units. For the purpose of rationalization, an automatic changer in combination with an automatic device for cutting and cutting the test specimen sections would also be desirable here. Such devices are expensive, however, and their price is out of proportion to the relatively modest cost of the scale including the computer.