İDetection and removal of foreign materials on the wool fiber coming to the spinning mill is important in terms of determining the quality characteristics of the yarn to be made.
Wool fiber usually comes to the spinning mill washed and cleaned.
Foreign materials that cannot be removed by washing create problems during production.
A test is performed in the quality control laboratory to measure the amount of these foreign substances.
The reason for the procedures to know the amount of foreign matter;
1-Knowing how much foreign matter is in the fiber commercially,
2-It should be known in order to adjust the cleaning degrees of the machines according to the amount of foreign matter.
Despite the precautions taken from the places where the sheep roam, sand, dust, fertilizer, feed, thorn pieces, hook, litter, etc., due to the stickiness of the wool wax on the fiber. foreign matter sticks.
Most of these substances are removed by washing and carbonization processes.
Washed wool contains 20-80% foreign matter.
The amount of foreign matter varies according to the breed of sheep, climate and grazing conditions.
Pre-washed wool contains 15% foreign matter.
The impurities of raw wool can be classified as.
1-secretions excreted by the skin
2-wool oil
3-wool sweat
4-Skin rashes
5-Mechanically attached substances
6-Foreign substances from the soil (sand, dust, soil, etc.)
7-Vegetable foreign materials (grass, straw, fodder, thorns, thorns, garbage, etc.)
8-Other impurities
9-Residues of urine and dirt
10Leather chipper as a result of shearing errorthe k
11-Dyed, bituminous, burnt fiber ends
The presence of foreign substances in the fiber causes the problems listed below.
1-fiber breaks
2-Dust formation
3-Increase in yarn breaks
4-increase in telephone
5-Challenges in the future
Sample Preparation
A representative sample is taken from each wool lot.
A laboratory sample of 500 g is separated from this representative sample.
Two 100 g test samples are separated, taking care not to spill the foreign substances in the samples.
TIf foreign matter inspection is required, a 500 g test sample is separated from the 200 g laboratory sample.
Weighing, conditioning and testing of laboratory samples should be in the same room.
For this purpose, the recommended atmospheric conditions should be left at 65±2 % and 20 C±2 temperatures for at least 4 hours.
Determination of Foreign Matter
Foreign matter determination is made by two different methods. these:
Foreign matter detection by manual separation
First, garbage, different colored fiber and nope measurements are made on the light table of the sample taken. Nope detected on the lighted table, different colored fiber or garbage is taken with a pliers.
individually sorted and collected in a box. After the sample is completely free of foreign matter, it is weighed and the percentage is calculated over 100 g. The wool fiber to be used is evaluated and decided before production.
Foreign matter detection with the Shirley analyzer
Foreign matter and clean fiber eyes of the device are thoroughly cleaned and adjusted.
On the same day, if the device has not been operated before, the feeding cylinder is deactivated and the fan valve is fully opened for 2 minutes.
The sample is scanned 4 times on the device.
First scan
If the inspected material is fleece, 100 g – if waste, 75 g sample is spread in small tufts across the width of the feeding table and the device is started.
The materials that start to spill into the foreign material section are visually inspected.
After the entire sample has passed under the feeding roller, it is waited until there is no fleece on the cage and the machine is stopped by opening the feeding arm.
The fibers are taken from the clean fleece chamber (L1), the garbage (T1) is left in the tray.
Second scan
The fibers are passed through the device a second time.
Only this time, half of the sample amount is spread on the feeding table as a sample layer, and the rest is added later.
L2 fibers provided at the end of the second pass are set aside. T2 garbage accumulates above T1.
Third scan
The fibrous part of the material (T1+T2) accumulated in the foreign matter tray is spread in the middle of the feeding table and passed through the device.
At the end of the transition, L3 fibers are obtained.
T3 foreign matter is left in the tray.
Fourth scan
L3 fibers are passed through the machine again.
The resulting L4 fibers are combined with the previously separated L2 fibers and weighed with an accuracy of 0,1 g.
The total fiber amount is noted as L=L2+L4.
T=T3+T4 foreign matter accumulated in the tray is collected and weighed with an accuracy of 0,1 g.
While weighing the foreign matter, care should be taken to remove the fine dust accumulating on the feeding table and in the inner channels of the foreign matter tray and the pieces of hook and loop attached to the teeth of the receiving cylinder with a brush and add them to the scale.
One test is sufficient for wastes.
As a result of the experiment, the percentage of the amount of foreign matter in the fleece is determined and written.
Evaluation of results
Foreign matter, fiber and invisible loss amounts are calculated from the formulas below.
Amount of foreign matter:
Y=T/M*100, in percent
Fiber amount:
E=L*100/M, in percent
Invisible loss (flying fiber, dust), amount:
K=M-(T+L)/M*100, in percent
Here:
E=Percent fiber, K=Percent invisible loss, L=L2+L4 fiber amount g, M=Sample weight g,
T=T3+T4 foreign matter, g
GK=M-(T+L)
In wool, the results are given as the arithmetic mean of 2 experiments.
If the difference in the percentages of foreign matter obtained from the 2 tests is more than 20% of the small value, the test is repeated with the test samples to be taken again.
Formulas:
1. Weighing -L=L2+L4, 2. Weighing -T=T3+T4
Fiber %: L/M
Trash %: T/M * 100
% invisible loss (M–TL) / M * 100
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