ISO 2648-2020 pdf download.Wool一Determination of fibre length distribution parameters一 Capacitance method.
6.2 TestIng atmosphere
The test Is Lobe performed in the standard atmosphere For testing as defined in ISO 139
7 Sampling and preparation of laboratory sample
7.1 Sampling
Samples shall be taken from bales distributed equauy throughout a lol Only one sample shall be taken (rum a bale. unless the lot is smaller than S bales when an equal number of samples shall be taken from each hale,
To charactenze a lot, take at least one sample Irom each of S homogeneous portions of the lot to form the total sample For masses greater than 5 000 kg. at least one sample shall be added per S 000 kg portlon
NOTE Homogencous portion of the Int is a ball or bump at sliver, a can of drawing sliver, a roving bobbin, a sliver or roring taken directly Irom a finisher.
Samples shall not be taken for measurement from the disturbed outer layer, or immediately next to the core of a package. Slivers having adventitious thickness faults (especially abnormal thick or thin places) are to be discarded. Slivers taken directly 1mm a comb, cut or chopped slivers and those containing fibre bundles are also unsuitable, In such cases, the variatinn in fibre length between ucct%sive samplings is likely to be very large, potentially giving rise to significant errors.
7.2 Preparation of laboratory sample
72.1 General
To obtain a suitable lalioratnry s.implc. tiiwrs shall hi’ under semi-relaxed state, lo achieve this torrn. pre-treat laboratory samples according to Annex A.
7.2.2 Slivers of combed wool weighing between 15 g/m and 30 g/m
For slivers of combed wool weighing between 15 g/m and 30 g/ns, a length of about 1.2 m is broken oil from the homogeneous portion of the lot. Immediately alter sampling, the sample held under slight tension is given 36 turns of twist (30 turns/rn); held taut in this condition, it is doubled at its centre and its ends are brought together and held. See Annex A for details.
In this form, the sample can be stored indefinitely and can easily be sent by post in a plastic bag, or held fast on a tube of approximate diameter 40 mm in the twisted state, to the testing laboratory.
For in’mill management, the operation of twisting maybe omitted only when the ball of combed sliver or of roving is available at the moment of testing and lithe test is going Lobe carried out wIthin 4 h of sampling.
NOTE ‘This twisting operation Is thsoiulely essential in order to obtain accurate teu results.
7.2.3 Rovings or slivers weIghIng less than IS g/m
In the case of rovings or slivers weighing less than 15 g/m, sufficient 1,2 m lengths of sliver are successively drawn to build up. by overlaying, a sliver which weight per metre Is about 22 g (30 g maximum). At the time of the ovi’daylng, the slivers shall always be laid In the same direction (For example, the leading end as delivered by the mill machine always to the left).ISO 2648 pdf download.