Count Calculation of Folded Yarn in Tex System
Folded Yarn:
The calculations for ascertaining the resultant counts of folded yarns when the counts of the component threads are given in the direct or universal system like tex is very simple. This is because of the fact that the count number in these systems expresses the weight of one length unit of the yarn or thread. The weight of one unit length of folded yarn is equal to the sum of the weights of it’s component threads in one length unit. Therefore the count of the folded yarn will be also the sum of the count numbers of it’s component threads
As already stated, there will be some contraction in length when the component threads are twisted together. The resultant count number in the above two examples will be higher than the sum of the count numbers of the component threads. The reverse also holds good. Thus if a two fold yarn of 42 tex is composed of two single threads of identical counts, then the count number of each components will be slightly less or finer than 42/2 or 21 tex.
This is of course not very significant for ordinary cases. However, in the case of hard twisted yarns, special or fancy yarns, eg. Crepe yarns, cork-screw yarns, loop yarns, etc. this factor is very significant and must be taken into account. The count of the folded yarn in such cases will be much higher than the sum of the count numbers of the component threads.
The following formulas will be used during calculating count of folded yarn in tex system:
(1) To calculate the resultant count of the folded yarn when the counts of the component threads are known.
As explained in the above, the count of the folded yarn will be the sum of the count numbers of the component threads.
Resultant count of the folded yarn,
= weight of one length unit of folded yarn in appropriate unit.
= Total weight in appropriate unit of one length unit of component threads A,B,C
( where A,B,C are the component threads)
Or,
Resultant count of the folded yarn,
= Count of A + count ob B + count of C
Example 01:
Calculate the count of three fold nylon yarns, if the count of it’s three component threads are 28 denier, 29 denier and 30 denier.
Solution:
Resultant count of the three folded yarns,
= Count of A + count ob B + count of C
= 28 + 29 + 30 (where A= 28, B=29 and C=30)
= 58 denier
So, the count of three fold nylon yarn is 58 denier.
(2) To calculate the count of one of the unknown component thread when the counts of other components and the resultant folded yarn are known.
Count of the unknown component thread,
= (Weight in appropriate unit of one length unit of the folded yarn) – ( sum of the weights in appropriate unit of one length unit of each of A,B)
Where A,B………. are the known component threads .
Or,
Count of the unknown component thread,
= Count of the folded yarn – (count of A + count of B +count of C…………… etc.)
Example 02:
If the counts of a 3 fold yarn and it’s component threads A, B, & C are 36 tex, 11 tex & 13 tex respectively, calculate the count of the unknown component thread.
Solution:
Count of the unknown component thread,
= Count of the folded yarn – (count of A + count of B +count of C)
= 36 – (11 + 13)
= 36 – 24
= 12 tex.
So, Count of the unknown component thread is 12 tex.
